MTH Berk - Derailing A lot

[astrocling]

So I recently picked up my first steamer, a Berkshire by MTH. It is the Nickel Plate 775 Unit. I haven't had any derailment problems with any engines or stock on my layout but this engine seems to be pretty finnekey when it comes to staying on the rails.

My main issue seems to be with the front truck coming off and then it seems to go down hill from there. Nothing seems to be turn related, they are all happening around switches. Is there something I am missing here?

[Selector]

Steamers have long wheelbases under the bottom dead centers of those four drivers on each side, particularly those engines designed to move loads at speed, as the Berks were. If your pilot truck is lifting out of the outside rail on curves, it can be due to insufficient weight/spring tension to keep it down, or as likely, it could be a result of the rear two driver axles lifting the frame on one side over uneven rails. If you have a superelevated outer rail, say, but somewhere most of the way around the curve that outer rail dips unbeknownst to you, the frame will rise on the one side in compliance, but the outer wheels on the truck already running over the dip may be inclined to lift and cause the derailment.

One other cause could be flashing, crud, or some other mechanical impediment between the truck and its under-frame bearing or pivot point.

This is all assuming your curves are not in the 18" range in HO. Larger drivered steamers with four axles will do quite a bit better on 22" and wider curves.

What you must do, after you remove and inspect the bearing surfaces on the truck and the frame with your forefinger, and ensure it is lubed, is to set the loco properly on the rails and run it slowly through the place where it wants to derail. Note where the truck lifts. There is a dip there that must be mitigated a bit, perhaps only by 0.5 mm. Lift it. Alternatively, note if the loco cants to the opposite side on high rails if you have any superelevation at all. You may have to reduce it.

[railfan]

I don't know if this would work for you but on my layout I just put like a thousand rerailer track sections everywhere. Goofy me. It helps though!


Mike

[trailrider]

Originally Posted by astrocling

So I recently picked up my first steamer, a Berkshire by MTH. It is the Nickel Plate 775 Unit. I haven't had any derailment problems with any engines or stock on my layout but this engine seems to be pretty finnekey when it comes to staying on the rails.

My main issue seems to be with the front truck coming off and then it seems to go down hill from there. Nothing seems to be turn related, they are all happening around switches. Is there something I am missing here?

Have you checked the lead truck wheel gage? Make sure to check the gaging at several points around the circumfrence of the wheels, as one or both wheels might not be square on the axle, causing the wheel(s) to wobble. Where on the turnout does the derailment take place? Where the points meet the stock rails? Where the stock rails meet the closure rails? Does it happen as the truck goes through the straight part of the turnout, or on the diverging part? What brand of turnouts are you using? Does the derailment begin as the wheels enter or go through the frog?

As was posted, run the locomotive slowly through the turnout and see where the problem is occuring. Let us know, and perhaps we can be of further help.

[sd24b]

along with the checking wheel gauge, do they all sit on rails squarely? phil

[astrocling]

Ok guys so I took into account all of your advice and really found that it wasn't the turnout causing the problem. Following Selector's recommendation I slowly ran the engine through all areas of the track and found an area, who would have though in a turn , where one of the main wheels on the outside was derailing. The problem actually wasn't related to the front truck.

I managed to find an area that wasn't quite level, and leveled it out. It made the problem less frequent but I still got it every once in a while. Then I started measuring, and found that the turn, the first turn I ever hand laid (apparently quite hastily as well), started at 23' radius and in the center pinched to less than 18". Needless to say I tore up the entire turn and relaid it, and I can almost guarantee that this is going to solve the issue. I also took the time to glue down all my track and roadbed, which I think will help as well.

Thanks for all the help guys, this place is a great resource. I'll try to let you all know later this week if I get any more problems after the re-lay.

[trailrider]

The problem with hand-laying or even using flex track on relatively (compared to the prototype) tight-radius curves (24" and tighter) is keeping the exact radius of curvature. Because of tight space requirements on my latest layout, I couldn't quite manage even 22" radius, but wanted my main line to be easier curve than 18". I bought a bunch of 20" radius Shinohara sectional track from Wm. K. Walters. I use 18" on sidings, branch line, etc., where Atlas Snap Track of that radius works okay. Shinohara also makes sectional track in "odd" radii from 16" to 32".

So far as longer fixed wheelbase locomotives are concerned, I have pretty much solved that problem using Mantua locos as a basis for kitbashing. The trick is to make all the drivers except the end ones on their steamers blind, and shimming them up, and the flanged ones down by .010" so the center drivers don't touch the top of the rails. You can't see it unless you get right down at track level with a light behind the locomotive. I've made
4-8-2's, 2-10-2's amd 2-10-4's out of Mantua/Tyco Mikados, and 4-8-4's out of Mantua/Tyco Pacifics. They will all handle 18" radius curves without any problems, as well as #4 Atlas Custom turnouts. The insides of the cylinder blocks sometimes have to be milled or file out a bit on some of them, but a Dremel tool and a file does the job.