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Author Topic: Super elevated curves for open rainge fast freight  (Read 949 times)

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« on: July 15, 2017, 06:25:15 PM »

I am in the process of building a layout for fast freight with 1000 feet of main line, using four(4) Bachmann DD40AX Centennials dragging fifty-five feet (55') of Accurail 89' tofc/cofc flatcars at 103 smph. the total weight of the consist is about 23 lbs total. The train is at its peak operating speed using Super elevated curves, using Bachmann's  ez track 35 1/2 curved track, starting at .00 on the out side of the curve tapering up to center .080 then tapering back to .00 at the end while keeping the inside of the track at .00 .

My question is, is there suppliers that sell tapered track bed for super-elevating curved track?
« Last Edit: July 15, 2017, 11:51:30 PM by cheerfulchomperofcheese » Logged
A Derailed Drag Racer

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« Reply #1 on: July 15, 2017, 06:57:54 PM »

I'm gonna go out on a limb here, and say no.

I'm sure someone will prove me wrong.



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« Reply #2 on: July 16, 2017, 12:46:51 AM »

You could use 0.080" Bookbinder's Board, a.k.a. Davey Board, to shim the outside edge of the track. It's available from several places on-line, and some craft stores.


If at first you don't succeed, throw it in the spare parts box.

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« Reply #3 on: July 16, 2017, 11:42:41 AM »

Just a comment on your superelevation plans: 

Your post sounds like you will be increasing the amount of superelevation from the beginning to the midpoint of the curve, then starting to decrease from the midpoint.  That would not be prototypical looking.  The real railroads would have an easement to the curve, with the radius beginning at infinity and decreasing to the constant radius section in a smooth fashion.  In that same horizontal easement, the superelevation would start at zero and increase to its maximum value where the curve radius becomes constant.

The purpose of the easements on the real railroad is to make the centrifugal forces on the passengers and equipment increase at a comfortable and constant rate from zero to the constant value that occurs on the constant radius part of the curve , rather than by an almost instantaneous jerk to the side.  The superelevation likewise makes the curve more comfortable by making the force seem to go more "down" instead of "sideways".

On a model railroad, neither of these factors is really an issue, except for making the shape of the curves and the motion of the train seem realistic when we run our models.

There is quite a science to making easements to curves for real railroads and hhighways.  (Basically, the reciprocal of the radius, 1/R, increases linearly with distance around the curve, which makes centrifugal force build up linearly from zero to the maximum value for the curve.) 

On a model, it is just a matter of making it not look like a "train set" layout.  I am not going to try to explain easement layout here, but I will tell you that it does not have to be complicated.  There are several books that you can use to find methods for making easements for model railroads.  For instance "Track Planning for Realistic Operation" by Jack Armstrong (Model Railraoder Books) has an easy method using flex track.  If you do not want to use flex, you can get a similar-appearing effect by starting your curve with a piece of sectional track that is the largest made by your track manufacturer and then use sections of the available decreasing radii until you get to the desired radius for your curve.

Be advised that putting easements on curves needs to be planned well in advance of settling on your track plan, because it adds a lot of length and a bit of width to a curve, compared to just jumping from straight to your selected radius.  But, it really adds to the visual effect, as does superelevation when done right.

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« Reply #4 on: July 23, 2017, 11:26:51 PM »

The curves start with a .015, .040, .060, .060, .080, .080, .080, .060, .060, .040, .015 over seven feet in length, you cannot see the bank with the natural eye. I run multiple high speed consist with the following problems in flat curves, uncoupling, coupler creep, piggy back trailers fishtailing and falling off, flat car stringing, rail joiners loosening, prime movers braking traction and amping out. By implementing the Super elevated curves as stated and using proper weighting of cars, consists will run full speed with two DD4OAX Centennial and one SD40-2 and fifty (50) 89 foot TOFC Piggyback Flatcars with 100 piggyback trailers setting on the flatcar for two (2) hours full throttle nonstop unattended with no fish tailing. Operating this 1970’s Fast freight layout you start on level one. GP40’s at the Salt Lake yard (south end) and the Portland yard (north end) pickup freight cars from industries and delivers them to the sorting yards. SD40-2’s picks up the freight cars and moves them up to the second level yard for building up a train.  The built up trains generally consist of a mix of three to five centennials and SD40-2, fifty (50) to sixty (60) 89 foot TOFC Piggyback Flatcars with 100 TO 120 piggy back trailers. Mix of three to five centennials and SD40-2, 80 to 100, 50 foot box cars and 62 foot high cube cars. Three helper engines help the train out of the yard up to the third level main lines (2%, 1%, 2% grade for 45 feet). The Consists run in opposite directions for up to 2 hours (scaled time, how many scaled miles from Portland to Salt Lake = how many laps around the main line at full throttle. Or at full throttle how much scaled time does it take to go from Portland to Salt Lake = How much time spent orbiting the third level main line before dumping down to the second level Main line). This sets up how much time the two teams have to do the following task, while the first two trains are running on level three’s main lines, Salt Lake and Portland have to break up and build up a train in each yard on level two:
1. Moving the prime movers to the engine yard.
2. Moving the freight cars to the level one yard.
3. Delivering the freight cars to industry’s from the level one yard.
4. Picking up freight cars from industry and delivering freight cars to the level one yard.
5. Moving the freight cars to the level two yard. (approximately. 100 cars for Salt Lake, 100 cars for Portland).
6. Moving the serviced prime movers from the engine yard to the built up out bound train.
7. Receive inbound train and launch out bound train with helper engines.
You do this two cycles and the team with the fastest time wins. During the two cycles teams will draw cards that give difficulty’s such as: prime mover blows two cylinders reduce power to 60% to the next town change out prime mover. Crew change at the next town, stop for 2 minutes. (someone touches rolling stock you loose 2 minutes)  
Portland’s level two yard and level two main line has to share with long Passenger trains running. Salt Lake’s level two yard and level two main line has to share with WP’s long freight trains running.
Equipment for operation:
1.   27 each Bachmann DD40AX
2.   20 each Bachmann SD40-2
3.   20 each Bachmann GP40
4.   120 each Accurail 89-Foot TOFC Piggyback Flatcar.
5.   240 each Piggyback trailers.
6.   150 each 50' Plug Door Box Car.
7.   100 each 62' Union Pacific High Cube Double Door Box Car .
8.   5 each knuckle draggers (Bachmann Track Cleaning Tank Car)
9.    2 each Proto 2000 E6
10.  2 each Proto 2000 E6B
11.  2 each Proto 2000 E7
12.  2 each Proto 2000 E7B
13.  40 each Athearn Blue box Passenger cars

 This brings up two more questions:
1.   What kind of software is out there for matching engine speeds for large consists?
2.   What kind of DCC System do you need for running up to 30 engines at a time with 6 to 8 operators, with approximately 1000 feet of track?
« Last Edit: July 23, 2017, 11:58:56 PM by cheerfulchomperofcheese » Logged

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« Reply #5 on: July 24, 2017, 12:44:12 AM »

I'm a bit new to DCC myself, but I'll share what I can and I apologize in advance if my any of my knowledge is mistaken.

Answer 1:  I don't know of any programs that will automatically match speeds.  But there is a program called JMRI (Java Model Railroad interface) that is compatible with many DCC systems and gives a graphical representation of the speed curve on your computer and allows you to adjust the voltages.

Each locomotive is a little different, so you'll have to create a custom speed table for each decoder.  You can use a model train speedometer like the Accutrack II or Bachrus to measure each speed step and fine-tune the voltages from their readings.

Answer 2:  You'll definitely need a system that supports multiple power boosters.  I use NCE's system, Digitrax is good too, both have systems that allow for multiple operators.

Most decoders draw up to 1.5 amps, and boosters tend to add 5 amps.  So 30 locos times 1.5 equals 45 amps divided by 5 equals 9 boosters.

Use 14-gauge copper wire under your layout to deliver power to the rails every few feet and you shouldn't need to worry about voltage drop.

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« Reply #6 on: July 24, 2017, 10:46:47 PM »

Superelevated curves are not really needed in HO model railroading.  Even with toy train 18" curves, you can trains at full throttle with no ill effects.

However, superelevation does look good on scale model railroads.  I super elevated all my main track visible curve but do not elevate any siding curves.  This is very prototypical as sidings (passing tracks) are usually slow speed.  I elevate my main track, 36" minimum radius on visible track, by raising the out side edge of the subroadbed.  I use Donnacona fibre board as my subroadbed.  To raise the outside edge I use 1/16", 0625", balsa wood glued down starting about a foot into the curve at both ends.  For single track, I use four inch wide plywood  going to six inch wide for sidings..

The reason I leave a foot at each end is for the transition from level track to superelevation.  I then glue and temporary screw down the Donnacona, when the glue is glue, overnight, I then remove the temporary screw and lay track.  Simple system and it works well.


Roger T.

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