SOME DC steamers stalling on crossing

[trailrider]

I have a kind of strange, annoying problem with SOME of my DC steam locos stalling as they hit an Atlas 30 degree crossing. The problem seems to only occur with older DC only Manuta Pacific-based locos. By that I mean original 4-6-2's, and other wheel arrangements I kitbashed from that model. It does NOT happen with a 4-8-4 I kitbashed from the Pacifics, nor with any based on the older Mikados, including 2-10-2's and 2-10-4's. Even if the stall does not occur when the drivers roll on the insulated frogs, but when either six-wheel original tender trucks hit the same points I get stalls with the Pacifics, but the very same original rigid trucks with the 4-8-4 does not! I also get stalling when a 2-6-2 based on the Pacific has its 4-wheel tender trucks hit. Other locos with 4-wheel tenders, even sprung trucks with axle wipers do it.

Pretty aggrevating and I have tried checking for continuity, etc. with a multi-meter, and still haven't a clue. The offending locos don't stall on the frog of Atlas Custom Mark IV frogs, which are longer. Aside from trying to find a 30 degree crossing by another maker, I can't figure it out.

[bnsf971]

Sounds like the wheelbase of either the engine or tender is just right the pickups lose their connection. Next time one stalls, note where all the wheels are in relation to the crossing.

[trailrider]

Originally Posted by bnsf971

Sounds like the wheelbase of either the engine or tender is just right the pickups lose their connection. Next time one stalls, note where all the wheels are in relation to the crossing.

What I find confusing is that the 6-wheel tender trucks on my 4-8-4, which are exactly the same as on the other Mantua hogs don't have the problem. In re-checking my 2-6-2, which is based on an old model Mantua Pacific, it won't stall on the drivers, but the tender trucks, which are 4-wheel, stalls on the tender. I may try getting a different crossing, either another Atlas 19 deg. or some other brand, if I can find one of the same angle.

Thanks for the suggestion, however. I will keep trying...

[Iron Horseman]

Are these locomotives the type where the loco picks up power from one rail and the tender power from the other?

1. Check the crossing itself with a straight edge to see if it is bowed up or sunken down in the center.

2. Check the track on either side to see if there is some torque action going on. One rail lower on one side or the other. Could make the power from the tender loose contact with the loco.

Don't confuse the issue by comparing what other loco's do. Each one can behave differently even if they came off the factory line one after the other. Focus on the wheel placement (where on the track) when they stall.

[trailrider]

Thanks for these suggestions. I went out and bought a brand new 19 degree Atlas crossing and installed it. Same problem, same locomotives. HOWEVER, I did some careful checking and found that when the right rear driver is in the insulated area the right front driver is NOT making good contact with the track. The blind middle driver is apparently over the middle portion of the crossing rail. When I stick a small screwdriver blade under the right front driver, all three locomotives start up! This tells me that either (a) as you said, the crossing is either bowed up in the middle (remember this is a new crossing), or the blind center driver is lifting the right front out of good contact with the "hot" portion of the crossing. NONE of these three have received the shim treatment that my other steamers have. I have decided to place .010" brass shims between the frame and the brass bearings on the front and rear axles, with a .010" shim between the bottom of the axle and the cover plate. Because Mantua siderods are hinged between each driver this should NOT cause binding, but should lift the blind center drivers off the top of the rails.

As an alternative, I also bought a PECO 30 deg. crossing, which is shorter than the 19.5 deg. Atlas crossing. If I don't solve the problem by shimming the drivers, I will try to see if installing the PECO crossing will work. I would have to change one turnout on my track plan to a PECO which will be non-powered, but since it is right in front of my control panel, it won't matter.

I'll let you know what happens. Thanks for the suggestions.

[trailrider]

Well...I installed the new Atlas 19 deg. crossing, shimmed up, depressed the center, installed shims in three of the Pacific-base Mantua locomotives. Some help with one of the locos, and spotty with one, and absolutely no difference with the third! Finally got disgusted, and replaced the Atlas 19 deg. with a PECO 30 deg. Insulfrog crossing. PROBLEM SOLVED! At least on the main line. The crossing route, which leads into a passenger terminal, will require some realignment, and/or replacement of an Atlas Custom line turnout with a #4 PECO or a #6 Shinohara and manual actuation of the turnout (which is NO problem as the tunout sits right in front of my control panel), which I haven't gotten to yet.

CONCLUSION: If you are running DC (don't know about the newer DCC units) Mantua 4-6-2, 4-6-4 steam locos, AVOID the Atlas 19 deg. crossing!

Thanks, again, for your suggestions!

[Silverton]

I have been having a similar problem with short wheel based engines stalling while crossing my turnouts. I have several 2-8-0 brass United Ma&Pa, also some 2-6-0 Ken Kidder Porter Moguls, and a few 2-6-0 Mantua; all are of a small wheel, short wheel base. Anyway, every time they approach and are crossing my Atlas turnouts they stall.
On my older layout, I used atlas code 100 track and Peco Insulfrog turnouts and never had a problem. We moved, I have started a new layout using Atlas flextrack code 83 and some Atlas turnouts that I bought new some time ago, so decided to use those thinking a switch is just a switch, they’re all alike. Apparently not. Now I’m trying to decide whether to replace the Atlas turnouts with Peco Insulfrog turnouts. What do you think. When you replaced your Atlas crossover with a Peco, your problem seemed to clear up.

[trailrider]

Replacing the Atlas 19-1/2 degree crossing with the Peco 30 degree DID solve the problem! I did have to slightly realign the tracks leading up to the Peco, and did replace the Atlas #4 turnout with a Peco #4, I have some very vintage twin-coil switch machines in my parts box, and used it to actuate the Peco turnout in conjunction with an Atlas at the other end of what is essentially a cross-OVER leading into the passenger station. I forget who made these little switch machines, but they have a spring to hold the position. These springs always had a tendency to pop out, and get lost, as was the case with this one. However, the Peco turnout's spring-loaded points substitute nicely.

My main "problem" with Peco switch machines is the fact that they don't seem to have enough power to reliably throw the turnout points, and they must be oriented 90 deg. to the track, which can prove problematic in tight spacings. The Peco turnouts themselves are very good. The Insulfrog turnouts do NOT cause me the stalling problems with my Mantua and other shorter wheelbase locomotives that the longer Atlas turnouts and crossings do.

Happy Holidays!

[scroggin]

It could be that the flanges on the pickup wheels are too deep so they bottom out in the flangeway and lift the wheels up slightly off the rails a file in the flangeways fixes that problem.

[Silverton]

Scroggin - that's a good point and maybe correct. Last night I ran several of my United 2-8-0 Ma&Pa over the turnouts and was surprised that some of them ran through the turnouts without a hesitation and some stopped as soon as it came to the turnout. All of the engines are basically identical to each other, but some went through and some did not. Maybe the flanges are too deep for the Atlas turnouts and the Peco turnouts are just naturally deeper and can accommodate the wheels deeper flange. Maybe... I think I'll try all this over again and see. - Thank you