Bachmann Message Board

Discussion Boards => Large => Topic started by: Craig on September 15, 2009, 11:03:31 AM



Title: Figure 8 components
Post by: Craig on September 15, 2009, 11:03:31 AM
We've got a 14'x6' large scale layout under our HO layout. I'm giving my sons each a large scale train of the own. I'd like to add a 13'x5' oval inside of the 14'x6', and another inside of the 13'x5'. Since the inner most oval will be smallest, I thought I'd try to make it more interesting. Can anyone tell me off hand what components are necessary to achieve a figure 8 using the Bachmann 90 crossing? I'd also like to know the overall dimension of the basic figure 8 track plan. Of course it will be 4' wide. I'm wondering by what amount I will be able to elongate it. Thanks for any tips guys.

Craig


Title: Re: Figure 8 components
Post by: Joe Satnik on September 15, 2009, 01:28:24 PM
Dear Craig,

As close as I can measure on the screen, the actual crossing portion of the 90 degree crossing is 3-1/2" long. <-Error!: Hunt measured 11-7/8"


Dear Terry T. (or others that own a 90 degree crossing),

Please measure to the nearest 1/16th inch the rail top length of the G 90 degree crossing. 

Thanks in advance. 


Back to Craig,

Bachmann G curves try to imitate LGB 1100 series R1 curves, which are 1200mm diameter (=23-5/8" radius).   

A natural 23-5/8" radius 90 degree figure 8 would need ~18" long straights (times 4 legs) between a ~12"  long crossing and the 9 curves on each side (= 18 total). 

If you wanted to expand along the length in both directions, you would neet to cut two of your curves into 4 half curves, or buy 4 LGB 11020 half curves. 

If expanding along the length in only one direction, cut one curve into two half curves, or buy 2 LGB half curves.

I have new Bachmann G curves and straights to sell (set breakup).  If interested, joebarb"AT"wwt"DOT"net. 

Hope this helps.

Sincerely,

Joe Satnik   


Title: Re: Figure 8 components
Post by: Craig on September 15, 2009, 02:13:11 PM
Joe,

Thank for your reply. I've emailed you about your track, btw.

I wanted to know the basic figure 8 dimensions because I'd like to do something along the lines of my crude illustration, and I need to know the maximum lenght (and thus, how many more straights I need) the red sections will be. I have 13 linear feet to work with, less the basic figure 8.

(http://i32.tinypic.com/2lo3znn.jpg)


Obviously the layout in the illustration exceeds my 13' space constraints, but you get the picture. It should be possible to create the above diagram without modifying any track.


Title: Re: Figure 8 components
Post by: Joe Satnik on September 15, 2009, 05:32:20 PM
Dear Craig,

The base length of the natural figure 8 in my example above is 114" to the track centerline.  Because of the Big Hauler 4-6-0 cowcatcher overhang, though, you must add at least 3-1/2 to each side of the track centerline. 

So, "fence to fence" or "wall to wall", you would need 7 more inches, or 121" total clearance for the base figure 8 

But,

You would also have to be aware of underhang clearance on curves for the middle of long cars on the next oval out.

I haven't specifically measured it, but have found through experience making concentric ovals out of Bachmann R1 track, that if you have 1-1/2 more straights on each of the 4 sides of the next oval out, you will avoid overhang/underhang crashes between the Big Hauler cowcatchers and (long) passenger cars.

You said:  "It should be possible to create the above diagram without modifying any track."

Sorry, not true.  Bachmann curves are 30 degrees each, with no half-curves available.   

With the 90 degree crossing, you need to turn 45 degrees between the crossing leg straights and the expansion straights. 

This requires a normal curve plus a half curve (30 degrees + 15 degrees = 45 degrees). 

Even if you bought LGB (solid rail) half curves, you would have to remove the black blades that fit inside the hollow Bachmann rails. 

Your statement could be true if Bachmann made a 60 degree G crossing.  (Natural for figure 8s using 30 degree curves and expansion straights.)  They have chosen, however,  to put their efforts into locomotives, not track geometry, hence the mis-matched 90 degree crossing.<- Error! Turns out the 90 degree crossing with the included half straights is perfectly matched for the non-expandable figure 8.  My apologies.

Hope this helps.

Sincerely,

Joe Satnik

               


Title: Re: Figure 8 components
Post by: Craig on September 15, 2009, 05:50:02 PM
"Sorry, not true.  Bachmann curves are 30 degrees each, with no half-curves available."

Now that's disappointing. It makes me wonder why Bachmann sells the crossing. Still, cutting two curved sections in half to obtain four 1/2 sections isn't beyond my ability, or that of my power mitre saw. Thanks a bundle for the info, Joe.

Craig


Title: Re: Figure 8 components
Post by: Craig on September 15, 2009, 07:22:38 PM
Joe,

At your convenience, please check your e-mail. my e-mail address is broncomaniac and hotmail is the domain I use. Thanks.

Regards,
Craig


Title: Re: Figure 8 components
Post by: andyb on September 18, 2009, 07:14:47 PM
Just as an exercise I've had a go at drawing up possible layouts using the dimensions you've given, without cutting the curves (I reckon it is possible to construct an offset '8' figure but you may still have to cut the straights either side of the crossing to fit), see below:

(http://i753.photobucket.com/albums/xx178/andyb000/figure8.jpg)

Just to see how much room the standard 8 takes up I drew that first and then extended it by adding a passing siding at one end - you can purchase Bachmann turnouts separately - with the addition of some isolators you might just be able to fit two short trains on the layout and run them alternately (depends on the lengths of your locomotives and stock of course...)

Sadly, in this configuration, this doesn't give you any room to place the outer oval :( unless you can widen the board by say 12"?

But an interesting exercise in geometry...

Best regards

Andy


Title: Re: Figure 8 components
Post by: Joe Satnik on September 19, 2009, 06:20:38 PM
Dear Andy,

Nice diagram.  What program did you use to generate it?

How wide and long is the green tabletop shown?

Here's a no-cut G figure 8 recipe, though not expandable along the length as Craig had asked for:

Recipe deleted as crossing length was in error.  See recipe below.


Hope this helps. 

Sincerely,

Joe Satnik


Title: Re: Figure 8 components
Post by: andyb on September 21, 2009, 08:53:40 AM
Dear Andy,
Nice diagram.  What program did you use to generate it?
How wide and long is the green tabletop shown?
..
Joe Satnik

Thanks Joe - I used CorelDraw! v9 using a 12mm to the foot grid .

The green area is scaled at 13' x 5' to the edges but I don't believe this would give adequate clearance to add the outer oval and stay within the 14' x 6' specified.

Hope this helps?

Andy


Title: Re: Figure 8 components
Post by: Craig on September 22, 2009, 11:22:04 AM
Thanks to Andy and Joe for the additional helpful responses.


Title: Re: Figure 8 components
Post by: Craig on September 22, 2009, 07:02:31 PM
Joe,

I've acquired a 90 crossing and have experimented a little with your suggestions. I believe Bachmann should publish the formula you used to implement their crossing. I also feel Bachmann should market a "kit" to convert the small ovals they sell with their big Haulers into a figure-8. Your "no-cut G figure 8 recipe" would do nicely.

Thanks much,
Craig


Title: Re: Figure 8 components
Post by: Joe Satnik on September 22, 2009, 08:16:22 PM
Dear Craig,

Thanks for the kind words.

The next track to release should be a half curve, 

or a 60 degree crossing (of a specific useful length for R1 curves),

or both.

(60 degree figure 8s don't need the half curves.)

Offering half straights separate from the 90 degree crossing would be great.

A 30 degree crossing (of a specific useful length for R1 curves) would allow shorter length figure 8s. 

Half curves would allow expansion along the length of the 30 degree figure 8, in the same manner as they would help the 90 degree figure 8. 

Hope this helps.     

Sincerely,

Joe Satnik

   


Title: Re: Figure 8 components
Post by: Alex Butner on September 22, 2009, 11:41:05 PM
If I build a figure without modifications, will it work? I'm talking about a crossover, four straights and twelve curves. Will that work?


Title: Re: Figure 8 components
Post by: Joe Satnik on September 23, 2009, 12:06:48 AM
Dear Alex,

With a 90 degree crossing, you would need 9 Bachmann G curves per side, X2 sides = 18 curves total.

360 - crossing degrees = curve degrees per side.

Example,

360 - 90 = 270 degrees.

270 / 30 degrees per curve = 9 curves per side. 

I haven't added the extra crossing length to my old recipe yet. 

Tomorrow, perhaps.

Sincerely,

Joe Satnik


Title: Re: Figure 8 components
Post by: Craig on September 23, 2009, 08:34:55 AM
If I build a figure without modifications, will it work? I'm talking about a crossover, four straights and twelve curves. Will that work?

Without adding three more curves on each loop, you're just splitting a circle in half. There's no way for the ends to meet in the middle. As I've discovered, you can't  use the Bachmann crossing even if you do add six more curves. Joe Satnik has provided a list of the necessary materials, some of which (four half-straights) come with the crossing, to create a reasonably fluid figure-8. As Joe pointed out, his "kit" results in less than a half inch error over 64 inches. I think most of us can live with that tolerance.


Title: Re: Figure 8 components
Post by: Joe Satnik on September 23, 2009, 08:43:36 AM
Craig,

I calculated the "no cut" recipe using 3.5" as the length of the crossing, which was in error. 

As pointed out by Hunt, the length of the crossing is closer to 12".   

If my first "no cut" recipe works at all, it's because of luck and a lot of slop tolerance in the layout. 

I can definitely do better.

New recipe later this morning.

Sincerely,

Joe Satnik


Title: Re: Figure 8 components
Post by: Craig on September 23, 2009, 08:49:05 AM

The next track to release should be a half curve, 

or a 60 degree crossing (of a specific useful length for R1 curves),

or both.


(60 degree figure 8s don't need the half curves.)

Offering half straights separate from the 90 degree crossing would be great.

A 30 degree crossing (of a specific useful length for R1 curves) would allow shorter length figure 8s. 

Half curves would allow expansion along the length of the 30 degree figure 8, in the same manner as they would help the 90 degree figure 8. 

Joe,

I agree with you about the future product line augmentation, but in the mean time your "kit" would provide an economical, easy way to utilize the existing crossing with existing materials.

Half (and one-third) curves would allow us to build more interesting layouts than the figure-8. If we also had a 30 crossing to work with we could even build something along the lines of a 'twice around", which I personally favor many fold over a figure-8.


Title: Re: Figure 8 components
Post by: Craig on September 23, 2009, 09:48:24 AM
Craig,

I calculated the "no cut" recipe using 3.5" as the length of the crossing, which was in error. 

As pointed out by Hunt, the length of the crossing is closer to 12".   

If my first "no cut" recipe works at all, it's because of luck and a lot of slop tolerance in the layout. 

I can definitely do better. New recipe later this morning.

Sincerely,

Joe Satnik

Joe,

Upon further examination I find the "reasonably fluid" design to be much less fluid than I originally thought. Initially, I'd laid the components out without connecting them, and I accidentally substituted half straights for two of the full straights at the crossing when I did so(they were already joined).

This morning I moved some furniture and assembled one side of a figure-8 on my living room floor with a printout of your recipe as my guide. Once the track pieces were connected and "trued", even subtracting the roughly 6" at the crossing itself didn't help much. I'm looking forward to your next recipe, which hopefully will materialize before my wife gets home :~)

Craig



Title: Re: Figure 8 components
Post by: Joe Satnik on September 23, 2009, 12:56:29 PM
Dear Craig and All,

I have to apologize to Bachmann for criticizing their track dimensions.

It turns out that the  ~12" length of the 90 degree crossing, along with the ~6" half straights, work perfectly together with the ~24" radius (R1) curves to form a natural figure 8. 

The only thing missing is half-curves to allow expandability along the length of the figure 8.

No-cut, non-expandable natural 90 degree X R1 figure 8 recipe:   

One 90 degree x 11-7/8" crossing. 
1 half straight (~6")
1 regular straight (~12")
9 regular (R1) curves (~24"R x 30 degrees) all turning in same direction. 
1 regular straight
1 half straight
Hook up end of last half straight to 90 degree crossing.

Mirror image the other side.

If you cut two regular curves into 4 half curves, you would get expandability along the length:

One 90 degree x 11-7/8" crossing. 
1 half straight (~6")
1 regular straight (~12")
1 cut (R1) half curve (~24"R x 15 degrees) all curves turning in same direction.
8 regular (R1) curves (~24"R x 30 degrees) 
1 cut (R1) half curve (~24"R x 15 degrees) 
1 regular straight
1 half straight
Hook up end of last half straight to 90 degree crossing.

Mirror image the other side.

Layout dimensions:  52" x 119"

Minimum table top (fence-to-fence) dimensions: 55" x 122".

So, your (change your oval to a) "Figure-8 Track Pack" (kit) would need:

One 90 degree crossing (four half-straights included),

Six curves (or 4 curves plus 4 half-curves for expandability along length).

Hope this helps.

Sincerely,

Joe Satnik 

Edit: added "(change your oval to a) ... (kit)"  


Title: Re: Figure 8 components
Post by: Craig on September 23, 2009, 04:31:15 PM

It turns out that the  ~12" length of the 90 degree crossing, along with the ~6" half straights, work perfectly together with the ~24" radius (R1) curves to form a natural figure 8. 

Joe,

So they do.

(http://i33.tinypic.com/23th2jt.jpg)

I did not yet have a crossing when I started this thread or I might have saved you some math. I obtained a crossing after reading the responses I got here. I still don't have the extra curves I need, though thanks to you I now have a source for those.  Thank you for all of your help.


Title: Re: Figure 8 components
Post by: Joe Satnik on September 23, 2009, 09:16:34 PM
Dear Craig,

You can reduce your per-piece postage costs by increasing your order.  (Grin)

Thanks for the pic and the confirmation of my recipe. 

Now if we could just get Bachmann to produce those new track pieces.....

Sincerely,

Joe Satnik


Title: Re: Figure 8 components
Post by: Craig on October 20, 2009, 08:40:20 AM
Joe,

Thank you for the Bachmann G gauge track you supplied to me. The price was fantastic and I can't tell the "slightly used" track you sold me from the brand new track.

I will keep you in mind when the kids want to expand their Christmas sets, or if I need another circle of track for the tree downstairs.

Speaking of Christmas, how are you fixed for Bachmann Christmas trains?

Craig


Title: Re: Figure 8 components
Post by: Joe Satnik on October 20, 2009, 10:42:32 AM
Dear Craig,

Thanks for the kind words.  Glad I could help out.   

I have new (sealed in box) 90054 Christmas (Holiday Special) Annie Passenger - Trolley sets, complete or individual pieces (add an engine-tender or expand your consist, e.g.) 

I also have a new, box only opened for inspection, the matching 2-car Baggage-Combine add-on set.

G Track, too.

Contact info near the top of this thread.

Sincerely,

Joe Satnik



Title: Re: Figure 8 components
Post by: on30gn15 on October 20, 2009, 01:22:33 PM
Hey Craig, I can confirm that Satnik Satisfies.

Hey, Joe, there's a company slogan fer ya  ;) ;D

Point noted about figure 8 construction.

Have to make sure Kathy sees this too.
We got grandkids, middle granddaughter nuts about bugs, trains, woodworking tools, and fairies. nobody is ever going to completely figure that child out!


Title: Re: Figure 8 components
Post by: jsmvmd on October 27, 2009, 06:10:47 PM
Dear Friends,

Two questions:

1.  I did the +/- and did not see any reverse loops.  Right ?

2.  Are the frogs in the crossing section isolated ?

Thanks ! 

Best Wishes,

Jack


Title: Re: Figure 8 components
Post by: Joe Satnik on October 28, 2009, 11:03:49 AM
Dear jsmvmd,

1.) Two-rail Figure 8s by themselves do not create reverse loops that short out the power pack.

It's when people try to make a figure 8 inside an oval using 4 turnouts and a crossing that the reverse loops and shorts occur.

2.) The diamond rails and frogs look like non-conducting black plastic.   

(http://www.bachmanntrains.com/home-usa/products/images/uploads/94358.jpg)

Hope this helps. 

Sincerely,

Joe Satnik

 


Title: Re: Figure 8 components
Post by: jsmvmd on October 30, 2009, 01:03:40 PM
Dear Joe,

Thanks a  million !

Best Wishes,

Jack

P.S.  Are you a vendor?  If so, could you post your website or email, or email me?  I need some track and turnouts.  jsmvmd at aol period com
Thanks again !