Now that I am retired, I am in "get to all those long-awaited N scale locomotive maintenance / upgrade projects".
And coming around and updating old but very useful threads.
Everyone has been very helpful to me, I'm wishing to contribute in return.
Here is how we figured out, how to get the shell off both the Atlas/Kato U25B and the Atlas Classic U25B.
Here's the steps listed below. These shell removal steps work equally well on both the Atlas/Kato U25B and the Atlas Classic U25B. The shells from both of these locos interchangeably can fit on the other.
Because of these locking tabs on the walkway, my method that I've worked out and used successfully (using the tips by others including forum member SecretWeapon - thx!) is now as follows.
I did these steps last night as a quality control check, and they worked very well.
Overview:
1) Remove the hood part of the U25B shell first, separate from the walkways
2) Then, you can much more easily work the U25B walkways off by themselves
This applies to both the Atlas/Kato U25B's, and the Atlas Classic U25B's.
Re-installation is the reverse - I put the walkways back on by themselves, then put the hood shell back on.
Details:
Here's a verbal step by step. YouTube has several videos by others, showing exactly this process. It works well! Search YouTube for "atlas n scale u25b repair" and you'll find the YouTubes
that show these steps:
1a) remove the cab hand rails from their slots in the front rear of the cab
1b) from the rear of the U25B shell , very gently use a small jeweler's screwdriver to separate the hood shell from the walkway. Then lever and push up the hood shell from the rear, leaving the walkway in place.
1c) working my way forward, keep levering the hood shell upward gently. It will come away from the walkway (the walkway is still locked down due to the retaining tabs in the picture above)
1d) as you get close to the cab, make sure you already did step 1a, i.e. remove the walkway handrails from the cab slots. If you haven't done that, do that now. Assuming that's done, there are two retaining tabs at the rear of the cab, that lock the cab to the walkway. Gently levering both the shell and cab upwards, you'll be able to release those cab tabs
1e) once the cab is released, you're almost home free. keep levering the hood shell upwards from the rear until....
1f) you finally will get to the nose of the hood shell. Gently pry the hood shell upwards, *separate from the walkway*, from the front
1g) if all goes well, the hood shell will come free.... with the walkway still on the mechanism.
1h) Now, you can easily see / access the walkway locking tabs on the walkway, shown in the picture above (on the Atlas Classic U25B you couldn't see / access them easily before with the hood on and could too easily bend the copper power pickups going to the trucks... and on the Atlas/Kato models, there's a metal part of the mechanism preventing you from access the tabs from below anyway).
1i) Now you can gently spread those walkway's tabs apart, and gently start levering the walkway up from the mechanism. I start from the rear again, seems to be easier to access and spread the tabs there first.
1j) The next tip.... the walkway is a very tight slight interference fit on the *ends* of the mechanism. I need to gently lever the walkways up "level", so that I can "stretch' the walkways just enough to lever them off the ends of the mechanism. Look for interference fits, or MT coupler conversion adapters, that are "hanging up" on the ends of the mechanism. Work carefully here and eventually you'll be able to work the walkways off.
After 1j), if necessary I might file down the ends of the mechanism and inside of the walkway ends a bit, so that future removals will not be so tight.
Installation is the reverse - I put the walkway on first, then replace the hood shell.
Here's a picture of the tabs on the Classic, it's very useful to know of these slots and walkway tabs:
Here's a picture from Spookshow's Loco Encyclopedia of the Atlas/Kato U25B mechanism (
https://spookshow.net/loco/atlasu25b.html ), showing the same tabs / slot setup, on the older generation mechanism.
Again, you'll use the same steps outlined above, to remove the shell from this older generation model.
Again, there's several YouTubes out there showing exactly the steps above. Search YouTube for "atlas n scale u25b repair" and you'll find them easily.
