Bachmann Message Board

Discussion Boards => HO => Topic started by: ftherrmann on May 09, 2012, 12:41:45 PM



Title: Bachmann Locomotives limited to 2 degree grade????
Post by: ftherrmann on May 09, 2012, 12:41:45 PM
I recently purchased a 81661 USRA 4-8-2 locomotive.  Despite still having both its traction wheels it has “absolutely” no pulling power.  I have a 3 deg incline in my layout and this locomotive “spins” it’s wheels WITHOUT any rolling stock attached. If you attach two small cars it basically stops and spins. I have some of the other smaller, non-spectrum locomotives and they have at least 10 times the pulling power of this locomotive.

I also tried "Bullfrog Snot" in an attempt to get more traction.  The "Snot" improved things a little, but the locomotive is still basically useless for my layout.

I spoke with one of the Bachmann service people and they told me that Bachmann locomotives are limited to a two degree incline.  I didn’t find this stated anywhere when I purchased it back in Feburary.  I also don't find this to be the case with other Bachmann locomotives which are even smaller than this 4-8-2 and have at least 10 times the pulling ability.  If a 2 degree incline limitation is indeed the case shouldn't Bachmann state this in their marketing material?

Being limited to a 2 degree grade would mean that in order to have any type of over passes you'd have to have an enormous layout.  Most likely twice the size of a typical 4x8 ft N scale layout.

I've returned the loc back to Bachmann hoping for either a comparable loc replacement or finding a fix for this useless 4-8-2 loc.

Please tell me that this 2 degree limitation isn't true...
 
Fred


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: jonathan on May 09, 2012, 01:28:47 PM
Fred,

I have two 4-8-2s.  Neither came with traction tires.  Is this an HO scale locomotive?  None of my Bachmann locomotives have traction tires.  Oops; the standard 4-4-0 has 'em.

My 4-8-2s are among my best pullers.  The metal boiler gives them good weight over the drivers.  I have not found it necessary to add weight or traction. 

Confused...

Regards,

Jonathan


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: 2-8-8-4 on May 09, 2012, 01:33:26 PM
First--Original Poster--are you talking degrees or percent of grade, because there is a significant difference between the two?

A 2-degree grade is actually 3.49% (100% times the rise in inches divided by run)--which is more than most railroads ever had on a mainline.

A 3-degree grade is actually 5.24%--and most engines, real or model, should be spinning on that grade.

Actually, in the model world we generally expect our engines to pull way too much relative to the grades we have than the prototype engines could.

Second--I absolutely despise traction tires in general because they become a maintenance headache in the long run that can also affect the durability of the steam engine valve gear (increased stresses and wear patterns on the valve gear).

I am very thankful Bachmann chose to leave traction tires off the 2-6-0 and 2-8-8-4, and if the cars are properly weighted and roll properly, my 2-6-0's are pulling an adequate length of train.

John


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: ftherrmann on May 09, 2012, 01:59:27 PM
When the customer service rep made the statement she made no distinction between scale.  Based on this I assume it applies to all scales.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: wildpaws on May 09, 2012, 02:46:01 PM
When the customer service rep made the statement she made no distinction between scale.  Based on this I assume it applies to all scales.

Which still leaves the question unanswered, is your loco HO scale or N scale? If it's N scale, why would you be asking in the HO forum??
Clyde


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: 2-8-8-4 on May 09, 2012, 03:03:11 PM
Also--if you are calculating the distance required for one track to get up over another track, there are tables in some of the better layout books that do that for you.  However, the key criteria are how much elevation difference do you want between railheads?  And how thick is the overpass bridge (because that thickness must be subtracted from the elevation difference in order to calculate the maximum height of rolling stock that one can allow on the layout)?

And yes--a simple figure 8 up and over layout for modern (excess height) freight cars might possibly fill an entire 4' X 8' or 5' x 9' in HO--depending on the clearance chosen.

That's also why layouts the run along an exterior wall--with return loop(s) somewhere in a room to allow continuous running--might be preferred for "permanent" layouts.  They also take up less overall floorspace from a room, but require more complicated design and construction than the good old 4' x 8'.

I know that designing for "modern" equipment and/or full length passenger cars is all but impossible on a standard 4' x 8'.  That is reality in HO.

John



Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: richg on May 09, 2012, 03:11:21 PM
For those who did not look it up, 81661 is an N Scale loco. No idea if it comes with traction wheels.

Rich


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Doneldon on May 09, 2012, 03:26:25 PM
Rich-

Thanks for looking up the scale. I had noticed that the OP avoided that question. However, and to his credit, it doesn't look like he has multiple posts on the issue. Perhaps he's new to model railroading and doesn't understand what grades do to locomotives' pulling capacity. Even allowing for all that, it does seem that his loco is a little anemic. I'd like to know what it will do on level track.
                                                                                                                                 -- D


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: bobwrgt on May 09, 2012, 05:56:58 PM
Dear Fred

If you do a search in the N scale section you can find lots of information on the N SCALE light mountain not pulling it's weight. There are several solutions to the problem.

Bob


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Jim Banner on May 09, 2012, 09:29:18 PM
If it is pulling power you want, stick to diesels.  A four axle diesel is guaranteed to have at least four wheels on the rails, even if climbing a twisting track on a helix.  A steamer, on the other hand, is only guaranteed to have two wheels touching the rails on the same track.  To compound the problem, a diesel has all its weight on the driving wheels while  some of the weight of a steamer is lost to the leading and trailing trucks, assuming it has them.

Things are a little different in the real world.  The drive axles of a real world steamer are not rigidly attach to a rigid frame.  Rather, they are equalized with a complex system of springs, levers and linkages so that all drivers carry about the same weight, even on twisting curves.  This has been done on some 0-scale models and possibly on some H0 models although usually springing each end of each axle is as good as it gets.  In N-scale?  Not that I have ever heard of.

Jim


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Rangerover1944 on May 11, 2012, 11:25:28 AM
A 2-degree grade is actually 3.49% (100% times the rise in inches divided by run)--which is more than most railroads ever had on a mainline.

Excuse me!
 
http://i1150.photobucket.com/albums/o619/Rangerover1944/ascending_jacobs_ladder.jpg[/img]](http://i1150.photobucket.com/albums/o619/Rangerover1944/ascending_jacobs_ladder.jpg) (http://[IMG)
http://i1150.photobucket.com/albums/o619/Rangerover1944/incline.jpg[/img]](http://i1150.photobucket.com/albums/o619/Rangerover1944/incline.jpg)[/url

[url] (http://[img width=500 height=255)(http://i1150.photobucket.com/albums/o619/Rangerover1944/mt-tamalpais23.jpg)


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Rangerover1944 on May 11, 2012, 11:35:53 AM
I have had no difficulty with pulling power of my 4-8-2's either with some grades that are more than 3% hauling 10 cars. I'll post pics later of my grades, no where near the prototypical that I have shown, maybe 4%, and also I have more "terrible grade prototypical pics from here in the mountains of West Virginia". I know nothing about N scale and assumed the OP was referring to HO scale! Still don't know, since no confirmation. I'm also aware that as 2-8-8-2 said in his post that most rail roads had no grade problems. Except in mountain area's, that's why some brilliant engineers came up with "switchback" to achieve the impossible impassable mountains. Jim


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Rangerover1944 on May 11, 2012, 01:13:09 PM
This scenic train is still in operation today Cass Railroad Historical Society, West Virginia. Jim
[url(http://i1150.photobucket.com/albums/o619/Rangerover1944/hist_17log-1.jpg)][/url]


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: 2-8-8-4 on May 11, 2012, 02:17:28 PM
I'm also aware that as 2-8-8-2 said in his post that most rail roads had no grade problems. Except in mountain area's, that's why some brilliant engineers came up with "switchback" to achieve the impossible impassable mountains. Jim

A.  I never said that most railroads had no grade problems.  That is an inaccurate quote.  They actually had significant grade "problems".  What I said was that most mainline railroads avoided mainline grades over 3.5% due to both economic and safety reasons.  This by definition excluded logging railroads and some of those others who had little other alternative.

B.  I am a licensed professional civil engineer--and switchbacks are a horrible engineering solution, and those engineers were not what I would call "brilliant" either--they settled for the easiest, cheapest solution--perhaps they were forced to bow to the economic pressures of those railroad owners of the day.  Switchbacks involve excessive waste of time and resources to get trains up and over a mountain.  How many mainline Class 1 freight railroads still in operation today have a switchback?

To my knowledge the answer is none--I rest my case.  The economics and safety benefits of correctly designed railroad alignments put those railroads out of business--excepting some (essentially) tourist operations that remain who retain the switchbacks for scenic or other reasons--like perhaps to access the timber.

The correct engineering solution is to either tunnel through the mountain or use a series of cuts, fills, and curves to balance the grades to get them within reasonable tolerances.  Anything less is actually lazy engineering.  In the long run the operational costs of operating a poorly designed and built railroad will exceed the money saved during initial design and construction--which is why most of those railroads that featured the excessive grades are now out of everyday freight usage.

John


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Joe323 on May 11, 2012, 03:03:39 PM
There are a few railroads purposely build to go up moutains (Pikes Peak and the Carmelit Subway in Israel) come to mind but these are passenger not freight Rys 


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: rogertra on May 11, 2012, 03:31:34 PM
We'll try this again as my previous post seems to have disappeared.

Rangerover

2-8-8-4 wrote : -

"A 2-degree grade is actually 3.49% (100% times the rise in inches divided by run)--which is more than most railroads ever had on a mainline."

The photos you've posted under "Excuse me"  are of the Mount Washington Cog railway and what appears to be rope worked inclines on an ex UK colonial railway and subsequently the Cass Scenic Railway.  None of which could be classified as "mainline" as referred to in 2-8-8-4s original post.  So, the examples you've posted carry no weight to further your argument.

Steep grades, approaching 4% may be acceptable for a roundy-go-roundy 4 x 8 foot railway but are really not acceptable for a scale model railroad and they are too steep to be realistic.  The now closed N&W ex Southern Railway Saluda Grade excepted.




Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Rangerover1944 on May 11, 2012, 03:49:41 PM
I do believe we are talking about steam engine era, the pics I have posted are probably 100 years old. I do have one that is the steepest incline ever in the US. In fact it was in Pittsburgh Pa. Monongahela Line and it only dis banned in 1961 used for both freight and passenger. I'm just saying about how steep some grades were during the time. Of course engineering, research and development over the past 100 years have greatly improved most everything that we see today! And no railroad would ever go over a mountain such as they did years ago but remember it was the steam era. The 2-8-8-2 articulated loco's was built for such work in mountainous regions known to negotiate tight curves and hauling power. Used here in West Virginia where they replaced the 2-8-2's. They didn't have to MU 2 of these to haul, one 2-8-8-2 replaced the consist. As you can see in the pic both freight and passenger cars ascending. Now that would be something to model for the time era.

http://i1150.photobucket.com/albums/o619/Rangerover1944/MonIncline1905.jpg[/img]](http://i1150.photobucket.com/albums/o619/Rangerover1944/MonIncline1905.jpg) (http://[img width=500 height=278)
Monoline 1905

Didn't mean to start a flame war! Go ahead criticize me! Just stating the facts with pics! Jim


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Rangerover1944 on May 11, 2012, 03:57:20 PM
Well I went a little off course with my post and not posting main lines, just saying that's all! The Cass Pic is here in West Virginia google search will cofirm that and it is still in operation like I said. I've been there a number of times and considering voluteering to help restore some of the Shays and Climax's, just haven't found the time. All lines here in West Virginia, including main lines, have some very steep inclines! I have no argument with anybody especially those who have never seen or traveled the trains here in west Virginia! Jim


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: 2-8-8-4 on May 11, 2012, 04:49:58 PM
Not trying to offend anyone or be offended, just trying to stick to the facts.

Even the glorious epitome of 2-8-8-2 design, the Y-6B, was not designed for sustained operation on ridiculous grades--I think the N&W mainline grades--worst case--were in the 3% range, and only for relatively short stretches.

Also, the Western Pacific--which is a marvel of civil engineering for its time, was finished around or about 1909--well back into the steam era.  It featured more than 100 miles of sustained 1% to 1.1% grades, if I am correct, through the Feather River Canyon.  Those relatively modest but sustained grades enabled them to offer competitive freight service for much of the twentieth century, both steam and diesel.  They used 2-8-8-2's during the steam era over that division, but it also was a very well suited line for diesel power--thus they dieselized very early by about the end of 1952.  One reason the line is little used today is its remote location--I don't believe UP has much traffic in that area, and they choose to use the other routes instead.  However, the WP had one of the best alignments of any transcontinental railroad--and it was built during the steam era--it was the last transcontinental railroad completed, and the alignment was possible in part because they had access to explosives that previous builders did not possess.  (The other part being that they followed the river).

However, even by 1909 folks were avoiding the construction of steep grades.

(BNSF's current design guidelines require very flat grades).

East of the Feather River Canyon, for the desert run to Salt Lake City, the WP trains were assigned to a group of six marvelous challengers that were virtual copies of the UP Challenger--but in my opinion were much more attractive locomotives with nicer looking domes.  Because they toiled in the Nevada Desert, they were rarely photographed and are largely forgotten today.  Unfortunately for steam fans, the alignment of the entire WP plus the hard water conditions of the desert made it an ideal candidate for diesel power, so the beautiful monsters of steam passed too quickly...

John


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Rangerover1944 on May 11, 2012, 05:06:47 PM
Steep grades, approaching 4% may be acceptable for a roundy-go-roundy 4 x 8 foot railway but are really not acceptable for a scale model railroad and they are too steep to be realistic.  The now closed N&W ex Southern Railway Saluda Grade excepted.


Hey it's my pike, I created it and it is a little more than a 4x8 it's small at 11x17 with a subway under it. Lots of mountains and tunnel's with overpass's and anybody that's seen it hasn't complained one iota. If they did "I'd show them the door and wish them a good day". What's even worse to some model railraoders probably is that I still use the Bachmann EZ Command, have been for 7 years but program with Digitrax PR3/JMRI. I'm quite satisfied with it including my spaghetti bowl of trains criss crossing over and under bridges that have the 4% grades on one of the peninsulas  and the same as the subway ramp from the top to the subway! Got to put a couple pics of this bad-boy layout on this site. Idea was taking from an old Atlas layout magazine from the 60's and in fact was supposed to be modeled in the Colorado Rockies. Wish all you folks have as much fun as I do creating and enjoying your own pikes! Jim


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Rangerover1944 on May 11, 2012, 05:19:45 PM
I guess you guys picked up on the OP's original question. I didn't pick up on it till I read the part (traction tires). Definitely N gauge! Jim


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: rogertra on May 11, 2012, 05:24:52 PM
"Didn't mean to start a flame war! Go ahead criticize me! Just stating the facts with pics! Jim"

No flame war here buddy, but the the photos you post do not back up your argument defending excessively steep grades on main lines.

You are posting photos of cog railways, rope hauled inclines, logging roads and funicular railways, none of which is a "main line" or class one railroad.  They are tourist railroads or logging railroads.

I believe it's generally accepted that the ex Southern Railway and latterly N&W 4% or so Saluda Grade was the steepest "main line" or class one railroad grade in the U.S. of A.  And that steep grade is an exception to the rule.

However, if you want 4% or steeper grades on your model railroad go ahead.  As they saying goes, it's your model railroad.  However, the usually unmentioned other side of that coin is that it is most often used to justify unrealistic or unprototypical modelling.

But do what you want and have fun doing it.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: jward on May 12, 2012, 01:54:00 AM
 How many mainline Class 1 freight railroads still in operation today have a switchback?

To my knowledge the answer is none--I rest my case.  
John


look up hagans, va. the l&n cumberland valley line has a double switchback which is still used to-day by csx. and yes, full sized trains run over this line. thye break the train into two sections to run through the switchbacks, and reassemble the train on the other side. i was fortunate enough to ride this line in 1978.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: 2-8-8-4 on May 12, 2012, 09:36:43 AM
Well--imagine that--I stand corrected :)

However, the use of switchbacks is still far from the norm.

OP, and others with very steep model grades partly due to space--absolutely, yes, it is your railroad and you should be able to run whatever it is on earth that can run on your railroad that makes you happy.

However, it is a little bit unrealistic to expect model locomotives to negotiate grades with train lengths that the real engines never could.  That was the main point I was attempting to make.  At least within HO (I can't really speak for the other scales) many people try to push the limit beyond anything that was remotely possible in the real world.

Best wishes to all.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: rogertra on May 12, 2012, 01:41:26 PM
2-8-8-4 says: -

 "... it is a little bit unrealistic to expect model locomotives to negotiate grades with train lengths that the real engines never could. "

I think the reason we do this, at least this is the reason I do this, is that we are modelling in a restricted space.  Most of us do not have an Olympic sized gym in which to build our model railroads.  My now gone GER was built in a 12 x 16 foot room.  The model was set on the border southern Quebec and Maine, just in the foothills of the Appalachian Mountains and the railroads in this region were still fairly flat and grades were easy. 

However, in a 12 x 16 foot space I needed grades that would enable me to have visible tracks pass over hidden tracks.   This means a 31/2" rise in order to gain the required clearance.  This was done by using a descending grade for the St Pierre branch track that was eventually hidden and a rising main track grade for the visible track, thus splitting the need for the 31/2" height in half.  While that worked fine for me to pass the main track over the St. Pierre branch at Fox River, it didn't help in the climb from the hidden main staging where the grade was around 3% and on two 28" radius curves with a run of some  18 or so feet.

Even split grade solution gave me visible grades that were, for the region, unprotoypically steep yet I still need my steam engines to pull 16 cars plus van so as to give me a somewhat realistic and good looking train length in relation to the room size.  Scenic effects reduced the visible impact of the grade but it was still there and my steam models were still required to pull 16 car trains.  This is the reason, and I think it's a good and justifiable one, why we require and even need our steam engines to pull loads up grades that the prototype would have struggled with or found impossible to handle.

I have not mentioned diesels as they are usually not an issue, being far better pullers than steam and besides, you can always use multiple diesels.  And no, double heading or using helpers on my steam hauled trains was not an option as they were not used in the region I was modelling.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Pacific Northern on May 12, 2012, 03:42:31 PM
The CPR mainline first built through British Columbia contained a stretch of track know as the "Big Hill"

This section of track had a 4.5% incline. CPR built a siding just to store pusher engines to help with the various trains passing through.

At the time of the construction, most railroads were still using 4-4-0's as their main engines. In 1884 CPR ordered two 2-8-0's from Baldwin just for pusher duty. At the time these engines were built they were the largest engines built. In 1886 CPR ordered two more of these engines and in 1987 started building their own in their shops.

In 1909 this stretch of mainline was replaced with the "Spiral Tunnels" which lowered the incline to 2.2%


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Desertdweller on May 12, 2012, 04:40:43 PM
I have no documentation for this, but I think the last mainline use of switchbacks was on the Denver and Salt Lake Ry. to climb Rollins Pass.  This route was eliminated with the opening of the Moffat Tunnel.

Prior to this, switchbacks were used to get the Great Northern main line over the Cascade Mountains.  They were eliminated with the construction of the first Cascade Tunnel, in turn eliminated by the present Cascade Tunnel.

My last railroad assignment was on a railroad with a short distance of 6 per cent grade.
While technically on a main line, it was on an extension of the main line from its northern terminal north into a mining district.  So it only saw mine runs.  This was Cobre Hill near Baird, New Mexico.  Empties up hill, loads down hill.  This line was reopened about the time I retired, and I never ran a train over that stretch.

Switchbacks used to be a common way of getting trains over rugged territory.  They were common on narrow-gauge lines in Colorado, and were sometimes found on standard gauge railroads, but only as a temporary measure.  The Winona and Southwestern Railroad in Minnesota used switchbacks to handle the grades crossing Bear Creek Canyon in Winona County, MN until a high bridge was built.

I've run trains on industrial leads using switchbacks, and I didn't like them.  The first one I ran on was in downtown Hartford, CT.  Our railroad, the Connecticut Southern, used a switchback to get down into the Connecticut River Valley to serve a couple of recycling plants.  As is usually the case, the tail track (stub track) of the switchback is too short to hold a full spot of cars, so the switchback has to be doubled in both directions.  Someone with a sense of humor put an old road sign at the wheel stops at the end of the stub, "Bump"!

A worse case exists at the huge copper mine in Hurley, NM.  Here a steep grade leads downhill from the yard into the mine.  It ends at the stub end of a switchback.  There is a derail at the very end.  Beyond that is a more-or-less 200 ft. drop.  Again, the switchback stub only holds half a spot of cars.

The track leading back down from the switchback to the unloading tracks is maybe 4 per cent.   It goes down into an open pit mine.  18 car cuts of loaded acid cars are pulled into the mine, cut into two 9-car sets, pulled to the end of the switchback, and lowered into the mine for unloading, after pulling the two 9-car cuts of empties back onto the switchback and set out of the way.  It is quite a challenge for the engineer.  You have to set a lot of air (but not all of it, or you'll stall) and shove against the loads downhill, pushing against the brakes.  Stopping is achieved by chopping the throttle.
If you miss your spot, then you have a real problem!

Now that the concentrator is in operation, the loaded tanks are joined with empty gons inbound, and very heavy gons loaded with copper concentrate outbound.  It is an operation that requires a lot of focus.

Les


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Doneldon on May 12, 2012, 05:45:10 PM
There are a few railroads purposely build to go up moutains (Pikes Peak and the Carmelit Subway in Israel) come to mind but these are passenger not freight Rys 

Joe-

I don't know about the Israeli railroad you mentioned but the Pike's Peak Railway is very unconventiomnal and completely unsuitable for actual transportation beyond the reason the railway was built in the first place: Tourist access to a desirable point before automobiles were widely available. The M&PP is an inclined railroad with a gear underneath which engages a cogged "bar" between the rails. The Mt. Washington Railroad in New England is another example of this construction technique. But where can a cog railroad go once it's off of its incline? The cars are all severely slanted so people can't even stay in their seats once the cars go to level.

                                                                                                                               -- D


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: jward on May 13, 2012, 10:34:48 AM
i don't know about how anybody else does things, but having a steep grade can be useful if you want to run helper engines. on a typical basement sized layout, having a stretch of 3% forces 20-25 car trains to either get a helper on the rear, or double the hill. both were and still are common situations in real railroading. so, rather than being "unprototypical" these grades make the layout more true to the big ones.

remember, you can model everything to exact scale and not have much, or you can selectively compress everything and get alot more even if it isn't strictly to scale. 20-25 car trains are much more practical than the 100+ car monsters rolling by the house every day. and compressed trains need compressed grades to compensate.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Doneldon on May 14, 2012, 01:53:02 AM
i don't know about how anybody else does things, but having a steep grade can be useful if you want to run helper engines. on a typical basement sized layout, having a stretch of 3% forces 20-25 car trains to either get a helper on the rear, or double the hill. both were and still are common situations in real railroading.

Jeff-

I don't think doubling hills happens much at all these days due to the ready availability of strong, reliable motive power and the fact that trains can, in essence, take their helpers with them. A train's engineer can idle extra engines, saving fuel, but get them pulling upon reaching a grade. This is cheeper in the long run than having almost as many locomotives plus a large contingent of additional engineers standing by at the foot of every significant grade. But I certainly agree that building layouts so we can justify helper service is a great way to add some fun and, at least for railroads modeling the period when separate helpers were much more common, some complexity and operational realism to our miniaturized worlds.
                                                                                                                             -- D


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Desertdweller on May 14, 2012, 02:22:07 AM
Don,

It all depends on the railroad.  Many shortlines do not have enough loco units to send enough out on each train to handle the steepest grade without doubling.

On the Carolina Piedmont main line west of Laurens, SC, we have a siding at the top of the grade named "Dublin".  Because that was where you had to put the first cut of cars when you were "dublin" the hill!

Les


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: jward on May 14, 2012, 02:33:24 AM
don,

doubling the hill is rare on the mainline but fairly common on branchlines and shortlines. when i worked with the railroad, we did it every time we lost an engine and couldn't make the hill, this was on a train which used 2 sd80macs on each end. the loss of 5000 hp due to unit failure on a 14000 ton train can make you stall out.

we also had an incident on the b&p where using the helpers at full power rolled the rail over underneath the train, putting 23 cars on the ground. after that, we were required to double mosgrove hill.

in addition to those situations, i've seen it done as standard practice on the western maryland in west virginia, out of laurel bank. it was also done on the southern up saluda mountain in north carolina. pennsy did it as well between osceola mills and tyrone, pa. like i said it was and still is fairly common.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Doneldon on May 14, 2012, 04:58:36 PM
Jeff and Les-

Sure, doubling happens on occasion on short lines, but it is truly exceptional on mainline railroads today. It's just too expensive for big railroads to have helper crews sitting around, not to mention that doubling creates choke points which would be enormous problems with the heavy usage seen on today's slimmed down railroads.

I'm not poo-pooing the fun of or need for doubling, just pointing out that economics and time pressures have made it a thing of the past except on some poorly capitalized short lines. I can't imagine any railroad which would continue to use the technique if they had a reasonable economic option not to.

Doneldon


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Desertdweller on May 14, 2012, 09:20:17 PM
Don,

I'm not sure what you mean about "helper crews sitting around".  Helper crews do not play a part in doubling.
When you double, you cut off enough cars from the head end that will allow you to make the grade with the remaining cars, which are left behind on the main line.  You take those extra cars up the hill and set them to a siding beyond the crest.

Then you go back down the hill light engines, and pick up the rest of the cars.  You add the cars you took up the first time, and continue on your way.

Helpers are a way of avoiding having to double.  You keep helper locomotives and a crew on a siding before the grade, shove the train up the grade, and cut off the helpers at the top.  Then the helpers go back down to await assisting the next train.

This is not a poor use of crews if you do not have adequate power for each train, or if the traffic flow is heavy enough that the helpers can be kept busy.

It is a waste of resources to carry extra locomotives for the entire run of the train, if they are only needed for the ruling grade.  You could cut those extra locos off and leave them somewhere after besting the grade, but it would still need another crew to get them back down the hill (remember, they now have the train between them and the head of the train).

The other option is to keep the trains light enough that they can be handled with the assigned power without having to double.  Choices have to be made as to what cars have enough priority to be handled on these trains.  Then the cars with less priority (like empty cars going back to their home railroad) can be gathered into long but light trains that can run with less frequency.

It is the job of railroad field managers (like Trainmasters and Yardmasters) to make these operating decisions in a way that will best allow the railroad to operate at a profit. The answer will not be the same for all railroads.

In general, doubling is a necessary evil.  It takes a lot of time, uses extra fuel, and can cause a train crew to run out of hours before they reach their terminal.  It is used only when the alternatives are prohibitively expensive.  And as you pointed out, it ties up a mainline.

Les


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: jward on May 15, 2012, 01:42:07 AM
don,

just wondering what you are basing your observations on.

there are alot of factors which enter into whether or not a railroad decides to double the hill. one that many not in the industry overlook is the tractive force of the locomotive vs the coiupler strength of the cars. too much power and you break a knuckle. or worse. i've seen the coupler head ripped from the shank, all because a gp50 lost its footing temporarily, then gripped the rail again. i've also seen a situation where the frame broke on a gp38, and the whole front platform bent upwards enough for the coupler to ride up over that of the first car. run too close to the limits of the equipment, and you risk catastrophic damage.better to double the hill and relieve some of the strain, than to pull a drawbar. do that and you have to double the hill anyway, in addition to having to set out a damages car, clear the drawbar off the tracks, etc. believe me, it is a pain and attracts alot of unwanted attention to the crew.

as an example of the forces involved consider this: an emd sd80mac generates 187000 lbs of tractive force. couplers are rated at 500000 lbs.  so using 3 sd80macs on the head end of the train exceeds the rating of the couplers. if you must run 3 on the head end you either isolate one of them, or run the consist at reduced throttle settings so you don't exceed the limits of the couplers.   


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Desertdweller on May 15, 2012, 02:30:15 PM
Jeffery,

I see you and I are coming from the same place on this one.

I once broke a 14,000+ton coal train in two on a 2 percent grade.  The train was powered by a mix of ES-44 and Dash 9's:  Three on the head end and and two on the rear (DP).  When I picked up the train from the BNSF at the interchange, the engineer said something about the DP units acting oddly.  They did not seem to be loading.

The first several miles were flat, and the head end power handled the train OK.  The grade started at about 1 1/2 per cent, and I got into run eight hoping to keep some momentum before the grade increased.  I left the DP power on line, mirroring the head end.  Not a good idea, as it turned out.  The rear units still were not loading.

As the head end entered the steeper part of the grade, the DP power suddenly responded to the run eight radio signal.  Now I had plenty of power, 8,000+ hp. pushing against a train with all the slack stretched out.
You already know what happens next.

After we got the train back together, I split the DP screen and ran the rear units at a lower throttle setting than the lead units.   When the train topped the grade, I put the rear units into idle for the rest of the trip.
On arrival at my terminal (where the train was interchanged to the UP), I contacted the BNSF mechanical department, and explained to the UP crew what had happened.

Les


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: jward on May 16, 2012, 12:07:00 PM
over here on norfolk southern's pittsburgh division, certain types of locomotives are restricted in the amount of power that can be applied in certain situations. i am no longer with the railroad, but the policies have not changed much since i was there. the locomotive fleet is divided into regular and "high adhesion" locomotives. basically, high adhesion includes everything from gp50s and sd50s up to the most modern locomotives, everything up to sd40-2s are low adhasion. this distinction is necessary because wheelslip controls evolved in about 1980 to a computer and radar based system which actually measures wheel speed against ground speed. the older systems detected changes in load of the traction motors. a slipping wheel lowered the amperage the motor was drawing, and the system would shut reduce the voltage to that motor, not the best solution on a heavy grade.

with the high adhesion locomotives, we were restricted to certain throttle settings when pushing on the rear, or using dynamic brake. full power was only used in these situations with permission on a case by case basis. when ns rebuilt the sd50s a few years back and replaced the sd40-2s in helper service with them, the engineers in the altoona helper poolhad to get used to running them in notch 6 instead of 8. they were used to pulling the throttle all the way out and shoving at full power. you can't do that with the newer locomotives. one of the things on the mainline that makes things worse is that you often have articulated intermodal cars in trains, which further restricts what you can do with the helpers. apply too much power to those and they pop right off the track. coal trains are nice because the load is evenly distributed through the train.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Terry Toenges on May 16, 2012, 07:00:29 PM
I really enjoy reading you guys' real life experiences. Very informative.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Desertdweller on May 16, 2012, 08:59:45 PM
Terry,

I'm glad to hear that.  I was getting concerned we were getting a bit off-topic. If we are modeling real-life situations, it may be helpful to hear about considerations that enter into it.

One thing that is extremely important to an engineer operating a full-sized train, but is overlooked in model railroad operations, is control of slack within the train.  Coupler knuckles are made of cast iron, and are the weak link in the train.  This is by design.  A coupler knuckle is relatively cheap and easy to replace compared to, say, a drawbar.

Running slack in or out in a train is something to avoid.  Slack can be either kept run in (against the locomotive), or run out (train stretched).  If you are changing from one to the other, it needs to be done as gently as possible.

This cannot be done on a model train, because a full-size train has a braking system that can slow the cars independently of the locomotive.  It can also be worked against the locomotive to control the slack.  A model train is like a full-sized train would be if the
air was not connected to the locomotive, and the air was bled off each car.  This is only acceptable on a full-sized railroad for switching short cuts of cars within yard limits.

On the other hand, a model train decelerating is much like a full-sized train slowing with dynamic braking with no air set.  All slack in, only the locomotive providing the retarding force.

But the model train uses worm-gear drive in the loco.  A complete cut-off of power will result locked drive wheels.  Flywheels will help only slightly.  It would be the equivalent of a full-sized locomotive chopping the throttle and jamming on full independent brake.

If some designer wanted to simulate the train-handling skills used by a locomotive engineer, he would have to design a system that would provide a braking force to the cars independent of power or braking applied to the locomotive.  A system like that would be applicable to steam locomotives as well as Diesels.

Les


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: jward on May 17, 2012, 12:40:42 AM
i'm glad others are enjoying the insiders perspective of railroading. i've always found the real ones much more fascinating than the models. it kind of puts the models in perspective.

as an example of what i am talking about, consider somebody modelling conrail in say 1982. many modellers would look at the locomotives rostered by conrail at that time, and try to collect one or two of each type. this would be highly inaccurate, as many types were not in service due to the economy at the time. even the oddballs which were still being used were concentrated in specific areas (sd45s and sd35s in altoona helper service for example) and thus would be rarely seen on other parts of the system. to be accurate, most of the fleet should consist of just 4 models: gp40,
gp40-2, sd40. sd40-2. a smaller number should be gp38, gp38-2.  finally, one each of a couple of types like b23-7 or gp30. this would be pretty close to what you'd have seen trackside on any given day on the mainline.

regarding slack, yes it is a major problem. in my area, we weren't allowed to use stretch braking where you pull against the airbrakes set on the cars. but the pittsburgh division is a series of ups and downs. getting the train over the mountain out of altoona was the easy part. getting it the rest of the way to conway required some skill. west of johnstown, there are 3 major hills, and several smaller ones to climb. slack is always either running in or out in the train. for this reason, even relatively lightweight trains often had a helper on the rear to keep the slack bunched.

many other roads use some form of locotrol or distributed power, but while pennsy and conrail experimented with remote controlled helpers they weren't successful. i believe it is due to questions about loss of radio signal between the master and slave units. in particular, there is a nasty place known as the slide, just after you top the mountain at gallitzen. eastbound, you come out of the tunnel about 30 feet higher than the westbound tracks, and drop down a mile long stretch of 2 1/2% grade until all tracks are the same level. if you don't have your train under control on the slide, you'd better hold on and pray. you probably won't make the bottom of the mountain in altoona. the last thing you'd want is an unmanned helper losing its signal while pushing you over the top.

it is interesting that the only form of distributed power i've seen in use here is on the local trains, called shifters. these usually run with a locomotive on each end, to facilitate switching manoevers. you don't have to run around cars with a unit on each end. since the advent of the "zombie" locomotives controlled by belt pack controllers, it is now possible to control a locomotive from a half mile away using the beltpack. if the shifter is running heavy, becoming a common occurance with all the sand cars making their way to the drilling rigs in the area, the crew will often run the rear locomotive using the beltpack to get them up over the hills, while running the lead locomotive from the cab in the traditional manner.

when i modelled in n scale, slack was a major problem for me, but not in the same way as the real railroads. micro trains couplers have a spring inside the coupler which controls the slack. on long trains of free rolling cars, often these springs set up an oscillating action. the locomotive is moving along at a constant, slow speed, but the rear of the train is starting and stopping as the springs stretch and compress. the solution is the concept of stretch braking in miniature. you apply a small spring on the end of the axle on one of the wheelsets on the caboose, and thus create enough drag to keep the slack stretched. the spring applies pressure between the wheel and the adjacent truck frame.


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Desertdweller on May 17, 2012, 02:02:27 AM
Jeff,

Good points there!
It appears that Altoona helper service was the last use of oddball types on the Pennsy, especially last of their type units.

I've run a lot of both BNSF and UP DP power.  When a DP unit loses radio contact with its master unit, it will keep on doing whatever its last instruction told it to do.  It then reacts to brake pipe pressure only.  If it senses an emergency brake pipe reduction, it will automatically drop to idle.

You can dump the air on the DP units the same way you would on a FRED, but if it isn't getting radio contact for control, you can't count on that.

Most of the units I have run were standard short line power.  All the units you named in your last post, plus some even older (GP7's and 9's, SD 7's and 9's.)  Several of the short lines and regionals I worked for had contracts with Class Ones in which we would use their power on unit coal trains and unit grain trains.  The coal trains generally used DP power.  We also had trackage rights to operate over parts of the BNSF and UP main lines.  One railroad served as a bridge route between KCS and CSX, and we forwarded trains over our main line with power from those two, swapping power at the halfway point so everyone's locomotives wound up back home.

I've operated long N-scale freights on club that had the bouncy coupler action you refer to.  That's a great idea to provide a little drag using coupler springs.

The full-size railroads I worked on didn't mind you using a little stretch braking if you didn't overdo it.  I know the big railroads frown on it, but it is because they feel it is wasteful of fuel.  These are the same guys who will lecture you that safety is the first consideration.  I know one guy who got fired for entering a siding on a downgrade under dynamic braking because he trying not to use stretch braking.  The rickety rail rolled over under the stress of the dynamic brake.  The defective trackwork was apparently not a consideration.

I can imagine a model railroad controller made like the desktop control console used with computer loco driver games.  A geared motor in a rear car could act as a generator for controlled dynamic braking, using the automatic brake handle on the console.

Slack action on m N-scale railroad is really not a consideration.  Almost all my trains are passenger trains.  Nine cars is a long train for me, most run six to eight cars.  My railroad is supposed to be flat, but I have to adjust my legs to keep it that way.

I model passenger operations in the 1960's because I have always been interested in passenger trains, and because they are unlike the trains I ran for a living.  I get to run all the neat stuff I didn't get to in real life: E units, F units, PA units, FA units.  Plus some I did run, GP's and early GE's.

Les


Title: Re: Bachmann Locomotives limited to 2 degree grade????
Post by: Ken G Price on May 17, 2012, 06:20:21 PM
Thanks guys, I also enjoyed the discussion. :)