Rack And Cog Railway Physics

Vern

Trainz Maverick
Not sure if this has been discussed previously, but in contemplating building a rack (cog) based project how we get the correct behaviour of any traction rolling stock, particularly if improvising as might have to be the case? Some rack railways have gradients as steep as 25% (1 in 4) so releasing the brakes is simply going to result in an uncontrolled "whoosh" down the hill, whereas anything with a semblance of real physics is not going to climb anything greater than around a 5% (1 in 20) gradient which is close to the 1 in 17 or thereabouts that is the maximum for adhesion worked lines in Switzerland.

The same principle goes for lines which included inclined planes to link the top and bottom sections of conventional railway, usually rope or chain operated (of which there were several in the UK).

The obvious solution would be that any trains on a purported rack section would need to be driven in DCC mode or even have the AI operate them, assuming even then they won't protest at the extreme demands on the traction and braking algorithms.
 
The rack has at least 2 pawls that keep on clicking away as you go uphill ... should it drift backward, the pawls dig into the rack tooth and stop the train ... In Trainz :hehe: This would be fun to control !
 
I think cyberstorm was your man for rack and pinion railways in trainz. Whether it can be adapted to modern version though?
 
Cog railways have to use dynamic braking to keep downhill speed.
Friction brakes would overheat if used continuously, so they are only used for stopping.
As for steam locos these are equipped with counter-pressure brakes.

Dynamic braking is no problem in Trainz if using a diesel/electric enginespec, but the key issue would be to avoid any wheelslip.
 
I spotted Cyberstorm mentioned in a couple of previous threads so will heck out his stuff. No particular prototype in mind yet, more evaluating whether it's feasible and worthwhile doing. Though as many cog railways are relatively short and self contained, it should be fairly quick to knock together something on an experimental basis.
 
Vern

The secret is to increase the mass and power, and increase the friction and braking value to match. If it is cable or cog powered then none of the normal values apply.

I did a lot of work creating a working version of the cable worked Ashley Planes, with pushers (Barneys) and all the speed and control problems were solved. In the end it was not the train AI that made me give it up, it was something simple that beat me. Bear in mind there were three inclines/planes of double track, which required bursts of code at the start, end, and the intermediate points which meant that commands got lost or delayed which caused chaos.

It is possible that it would have worked in T:ane, but those were pre-T:ane days and I was so frustrated and disheartened that I gave it up.

Google for Ashley Planes

If you are interested and I can find the stuff, I will sent it to you.

Peter
 
Checked out the Cyberstorm stuff but mostly 800mm gauge which won't work with standard gauge (Pike's Peak) or the Swiss lines. Ideally need a separate rack spline which could be laid down the centre of conventional track (which would also aid conversion later on to TANE standards, procedural track etc).

I have found a prototype which has a maximum gradient of around 11% so will have a little play with that, initially just using standard gauge track and AI or DCC driving to test. Either that or I'll have another crack at the Flam branch which is adhesion worked, but with a maximum gradient of 1 in 17.
 
Vern,

Here's an interesting cog railway project you might want to check out.

Mt. Washington Cog Railway

http://thecog.com/index.php

https://en.wikipedia.org/wiki/Mount_Washington_Cog_Railway

Located in Marshfield Station, New Hampshire, the line runs up to the top of Mount Washington, which is the tallest mountain on the east coast at 6,288 Feet. They have since added a bio-diesel locomotives to their fleet to replace their aging steam locomotives. The steam locomotives are rather interesting with their canted boilers tipped downwards to keep them level as they climb up the rack.

John
 
Back
Top