5122/5121 Switch Tracks

You obviously know what you are doing, to work on those switches. Have you ever run the Polar Express on 027 track before? My guess is that the chassis of that engine is too long and that something - wheels or roller pick ups - is shorting on the swivel rail of the switch, causing a momentary short, and thus the change in direction. Same goes for the tender depending on the style of the roller pick ups.

And those Madison type passenger cars are better suited for 031 curves, even though during the MPC years, they did come in sets with 027 track. But maybe the trucks are different now. I know Lionel is using a vertical spring mounted roller pick up on their newer cars with die cast trucks versus the plastic snap assembly still being used on cars with plastic trucks (and once used with die cast rolling stock trucks also). I've had some random trouble with these newer vertical spring mounted pick ups getting caught on switch tracks. And I'm using 027 track too.

As another observation, I run mostly smaller, shorter types of engines and rolling stock. But I do have some no-no track configuations, like "S" curves and switch tracks placed right off curves. And once in a while, I encounter an engine that runs good  over the whole layout except in the other direction, and then gives me trouble on one single switch track.

In those cases, I'll run the engine real slow though the culprit switch and see where the short is happening. And then I use a small piece of electrical tape to cover the one place where a wheel or roller is making contact with a rail it shouldn't be hitting.

I have before, just not with the switch tracks. And it’s weird because I would have the train go backwards over it and work, but when I physically turned it around it didn’t work then. But I’m sure the problem is that the locomotive is too long for those curves on the switch. 

Another observation, if you have ever had any postwar Lionel steam engines, the roller pick ups are much narrower. Most pick up rollers today have a slight bevel on each side of them, but some of them have gotten wider that even what they were during the MPC years and on. I'd be willing to guess one possibility for what is happening, could be that the roller pick up is hitting the ground swivel rail of the switch. Some of my K-Line rolling stock had wider rollers and those could be problematic for me.

But that engine is a 2-8-4, so it's not impossible that one of the flangeless driver wheels is hitting the center rail going through the curve of the switch track.

You might be able to do as I mentioned, and use some electrical tape, or even duct tape to cover part of the top and side of the swivel rail that is closest to the center rail. Or the part where you suspect you are having the trouble.

Might even be the widest portion of the center rail part of the switch track. When I've done that, it doesn't need to be real long, but the tape needs to fold over each side of that center rail. Once you figure out the problem area, I've read where some have used paint to insulate the rails versus tape.

The items should be able to run on any O27 straight track.  But those O27 switches could be an issue.  The rollers could be different on 5he new items, and are allergic to te switch.

Wild idea:  Have you tried a Marx O27 switch?  It might work better with your PE endine going straigjt.

I have 5121,2 switches on my layout with 027 curves. The PE Berk needs 031 minimum and won't run on 027. I've tried it and can say I went down in flames.

You would have to consult Lionel’s product literature for the absolute minimum curve the loco is designed to run on.  But all of Lionel’s sets now come with O36 Fasttrack.  O36 is the new O31; I personally wouldn’t build a new layout with O31 today.  And I personally wouldn’t use Fasttrack because I perceive it to be noisy.

If you’re determined to operate the PE Berk, I would upgrade your layout to Atlas track with O36 curves and switches.  My $.02.

There are a few issues of the PE and I think there a few min. radius too.

If you need a Berk to make tight 0-27 turns all day; you need a Berk Jr like a 2755.

I think they did a PE Jr, but not positive.

The bigger ones need 0-36 to be truly reliable imo.

Roller width/position / tape bit is also a good possibility though.

It isn't 100% compatibly just by brand; some things need "convincing" 😜

Adriatic,

The Polar Express set has always had the same "Berkshire Jr." that came out around the same time as the "Hudson Jr.".  The Berk continues in production.  The Hudson Jr. hasn't been released in years. 

The Berkshire Jr. has come with two motor variations (large & small) and two body configs (with and without handrails). 

As far as I know, the chassis and wheels have been the same o all of them.  They appear to be a little "chubby" for their size, which when combined with the longer wheel base may be causing the issue here.

Jon

Thanks. I tried a smaller locomotive and it works smoothly now. I will probably expand with O42 curves in the future, so I can run my other locomotive.