siding length (ho)

[gregc]

for a small HO layout (3'x11'), with minimum radius curves (15-18"), and intended for small engines and cars (0-6-0T, 0-6-6, 2 bay hopper), what would a minimum siding length be (switch frog to switch frog)? either in feet or number of cars?

 

[Rico]

That would totally depend on your preference, length of train, amount of switching you want to do.
If you'll be meeting trains there you may want it a train length long, for switching it would be more fun to have a shorter siding to make things interesting.

 

[stationmaster]

It should be a tad(2-4 cars) longer than the longest train that you would run. Or long enough that a passing thru train can clear the beached consist parked on the siding.

Bob

 

[gregc]

i'd also appreciate some comments on the following. (not to scale). after trying to build a loop, i'm trying a very simple point to point shelf-like layout, intended for a switcher engine and small cars. the curve radius on the right may only be 15", but hidden in a tunnel. the numbers on the track (e.g. 1") indicate height. what i like about it it it's effective length.

something i'm considering is having a coaling station for the front branch but fed by a siding on the upper branch.

  -                                                 _______________          -
  |   ______________________________2"_____________/               \         |
  |          _/__________________/___________                       \        |
  |         /                                \                       \       |
  |       /                                   \_3"________________    \      |
 24"    /   _______       _____                    \     \________     |     |
  |         _______\_1"__/____________________       \                 |     |
  |                       _coal_/             \        \               |    36"
  |    ____ ___  ______________________        \         \_____        |     |
  |   ____ /   \/______________________\____0"__\                     /      |
  |   ____| TT  |________________________/       \                   /       |
  _    ____\___/                                  \                 /        |
                                                   \_______________/         |
                                                                             -
    <-----------------------------  11' -------------------------------->

 

[UP2CSX]

The general idea looks fine but I'm not sure you have enough space to climb 3" with a reasonable grade. I'd have to see a scale drawing to know for sure but, as an example, you need 96" of run from zero elevation to 2" elevation to maintain a 2% grade. It doesn't look like you have enough room for that. You'll also be climbing the grade on a very sharp radius curve. That adds to the the effective grade because of the flange friction you have to overcome.

 

[stationmaster]

A 3" rise is way too much, unless you have a horse of an engine.

Bob

 

[gregc]

i was figuring that from the point marked as 0" to the point marked as 2" is > 96" which i thought is an acceptable ~2% grade. i was figuring from the rear passing siding (2") up to the end sidings inside the curve on the right as gaining an 1" over maybe 36" (3%). wouldn't this be reasonable for a switcher and just a few cars serving a siding?

if this is a problem, i can reduce the 3" to 2.5". but i assume that having track at even slightly different heights will be more interesting that simply keeping things flat?

 

[stationmaster]

The problem is the curve and the rise together. Switchers do not weigh very much, hence a reduction in traction. The addition of friction with the wheel flanges rubbing the rail on the corner added to the weight of the consist may be too much for a small engine to overcome.

Bob

 

[gregc]

so the acceptable grade for a particular train will be proportionally lower the tighter the radius of curve compared to the grade going up with very gentle curving?

so in my case, what might be an acceptable grade assuming an 0-6-0 switch pulling 5 cars around a 15" radius? 1% or just 1.5%?

i think this was the mistake i made on my previous layout.

 

[Rico]

If you could add a second loop and made a big "S" you'd be able to pull it off. Sort of half a figure eight?
It might not change your plans too much.

 

[stationmaster]

so the acceptable grade for a particular train will be proportionally lower the tighter the radius of curve compared to the grade going up with very gentle curving?

so in my case, what might be an acceptable grade assuming an 0-6-0 switch pulling 5 cars around a 15" radius? 1% or just 1.5%?

i think this was the mistake i made on my previous layout.

Exactly.

But, you could add a pair of traction wheels and help the engine out. Give it more "bite". My Mallet used two sets of traction wheels when it pulled the 239 cars. It DOES help. And, as I like longer consists, all of my steam engines have traction tires.

I also try (try being the operative word here) to go no higher than a 2% grade on my modules. I work with whatever the rise is as best I can. It doesn't take much of an elevation change to make a tremendous visual effect. One of the great things about this hobby is that subtle things make all of the difference.

Another problem that occurs on the steeper grades, cars becoming uncoupled. Nothing worse than a runaway to come back up the line.

Bob

 

[UP2CSX]

As has been said, it's not just the engines ability to haul cars up a grade. Cars will tend to derail and uncouple much more frequently on a grade, especially when you add a curve. Anything you can do to ease the grade will make things run a lot beter on your layout.

 

[gregc]

If you could add a second loop and made a big "S" you'd be able to pull it off. Sort of half a figure eight?
It might not change your plans too much.

i can't picture this without crossing over other tracks which now requires 3" of clearance. can you describe it more?

 

[Rico]

You'd have to move the TT and tracks a little more to the front, looks like you have a foot to the front? After looking again at your drawing, maybe the S curve wouldn't give you quite as much clearance as you pointed out. Now I'm thinking two loops with a line along the back, that would give you more run for the grade. You could put the turntable at the other end of the yard..... maybe on the upper level?
Ah heck, now I'm totally redoing the dang thing! Help!