Learning the hard way

What if you enter the spiral from the other direction?

Steep slopes work OK with short trains. But they also require one or more of the following operating techniques/strategies:

1. Constant attention to the throttle to give more voltage up and less voltage down the grade.

or...

2. Some means of supplying less voltage on the downhill side by isolating that track section and reducing voltage by some means (diodes, separate transformer or throttle setting, etc.) in that block.

or...

3. Locomotives with some sort of speed control electronics such as Proto2/3, ERR cruise commander, EOB, or Odyssey. ERR cruise is probably the simplest and least expensive (but not cheap!) retrofit for currently owned engines.

or...

4. As Dennis implied, experiment with different % grades for the uphill vs. downhill runs.

As far as the fallacy of learning all you need to know from a forum, newcomers should realize that there is still an important place for magazines, books, advice from local hobby shop personnel, and, above all, your own experiences. It doesn't happen overnight and the first attempts at layout building are seldom perfect. That's all part of the fun, and is what makes model railroading a lifetime hobby for many of us.

Jim

Bank the curve at the bottom. Same as a NASCAR has banked turns for high speed. Shims of 1/8 - 3/16 should be enough to keep the train on the track.

Instead of redoing the whole thing, just change the grade of the last 1/4 of the spiral to be something less, and that could help the locomotive.  Also, have you tried it with the coaches behind the locomotive?  Yes, it is still downhill, but they provide friction and will change the vector of the force on the locomotive as it enters the last curve, and it may be enough to keep it on the rails.

I had a similar issue. I'd do the two reccomendations above in tandem. I'd assume you don't need 100% of the clearance you have. I used some old banked o-27 track and it helped.

Thanks guys.

@Jim P. - I am running LionChief and Legacy on the layout. The Polar Express is the new LionChief-the spiral will be used only by it.

@Nelson W.- miter saw went to work - I made some 3 & 5 degree banking wedges- 5 degrees made it worse- the train flopped over

@Sinclair- the tunnel clearance is close, I can't raise the rails much more

I really didn't want to drive the train -just let it go up, reverse loop, down, reverse loop.

Jim, yes reading and executing are two different things. I was really close.

Sinclair, you know, I haven't attached the cars yet. One last hail mary.

Some of the problem is that the 2-8-4 doesn't like 036 curves. The distance between the front of the first drive wheel and the last pushes through the rails. I think that's why Thomas did well.

I changed the layout in case the cars attached won't help. Started from the leg of the L and up to the same point for a 3 degree slope. I am trying to get that mocked up and tested.

I visited a layout where the train used the same grade to go up as well as down, similar to yours.  It had conventional control and it used a relay, triggered by isolated rails on the reverse loops, to switch between two voltages to the track:  a higher voltage going uphill and a lower one going downhill.  I do not know the specifics on how he did it, but it worked well.

Ron

I do that with a trolley circuit which has grades. I run conventional. Just need some relays and diodes. In a worse case situation you can pulse it down the hill with a repeat cycle timer. You do not need cruise control.

Dale H

If you arrange the switches so you always go up the same side of the helix then you could simply isolate the down section and add a resistor to give you a voltage drop enough to slow the descent.

Al

Will look into a relay solution. I see the diagram,are there 2 turnouts? does the train always travel the same way or do you reverse it and go both directions?

Dale H

Might work if you isolate the down section center rails, hook that section to a second transformer set at a lower voltage, and connect the grounds of the two transformers. That would be about as simple as it gets. Good luck.

Ed Kaz

They are manual switches. I let the non-derail feature push the frogs on every pass. So, it alternates clockwise to counter-clockwise and vice-versa on each pass. I may use non-track powered remotes with no control switch for a power-assisted non-derail.

Good thought, ekaz. FasTrack is simple enough to isolate and I have a ZW-C with 2 180 bricks with 4 channels. I am only using three. I could set ,say, D to a lower voltage. That would be a failsafe even if the someone turned the remote to full throttle.

Thank you.

I do not see how that would work since the trains run in both directions, you would have to manually worked the throttles.  Also pickup rollers will jump the center blocks paralleling the transformer taps.

Easier to use one tap with a voltage dropper. Relay logic could establish train direction using 2 relays. The method is shown here for directional crossing gates.

www.jcstudiosinc.com/BiDirectionalCrossingGate

Dropping voltage with diodes and bridge rectifiers is shown here

www.jcstudiosinc.com/BlogShowThread?id=413

I think you would need 4 relays in all and maybe 5 bridge rectifiers to drop voltage.

From that cascade of diodes you would have 3 voltages, no drop,for uphill,-3 volts for flat surfaces and -6 volts for downhill. These voltages would be adjustable to suit needs.

One 18V transformer tap could run the relay coils. Another tap would supply track voltage in series with the diode cascade. If you could make an outside insulated rail all the way up the spiral or grade,I think you could do it with 4 relays. I do not know how easy this would be to do with fast track. Other wise you could do it with 10 relays, a much more cumbersome latching system with short isolated out side rails at the grade approaches. The 2 direction relays would determine whether the 2 grade occupancy  relay contacts cut or increase voltage on the grade when occupied by the train.

With this method,if only 1 train runs on the loop, no center rails would need to be isolated,thus no roller jumping problems,only the outside rail on the grades and 2 short sections at a distant place which would work the direction relays.. The power to the track would be determined by the position and direction of the train.

Dale H