Removing Athearn Blue Box GP40-2 Trucks?

Model Railroader General Discussion (Model Railroader)
1

I’ve got a HO scale Athearn Blue Box GP40-2 locomotive, which I’m using as the basis for an On30 diesel conversion. To this end, I’ll need to make some modifications to the chassis, most of which are drilling and cutting.

As such, I’d like to remove the trucks and motor while making these modifications, in order to avoid having metal shavings getting into the mechanism.

There appears to be some sort of clip or latch on the side, which when released may allow it to slide forward. However, I’m not sure how to release them. Has anyone else removed these trucks and if so, how do I go about it?

2

Easiest way to do it, slide a very small, flat blade under one side of the clip on the top of the trucks, and twist. (I use a small hobby sized flat blade screwdriver.) That clip will pop right off. (Be ready to catch it!)

This allows the truck to just drop right off from the bottom of the chassis.

Motor is more tricky, as it will be either molded rubber-like plastic, molded hard plastic with screws, or silicone holding it to the chassis. (Original was rubber-like plastic, but if it was used…)

3

Insert a small screwdriver into the bottom of the worm gear cover and pry up.

4

The plastic side frames are press-fit. Yes, you can gently pry them off. I tried replacing the incorrect Blomberg-M with correct Blomberg-B on my blue box D&RGW GP40-2 and it was extremely hard to get them to press on.

5

Here’s an Athearn truck with the top clip removed…

I also replaced the metal strips used for power supply with wire, which explains the slightly different appearance.

I recall that some of those press-on sideframes are a pretty loose fit. It sometimes helps to cut a strip of paper to about the same width as the length of those mounting pins, then cut a short piece off the strip, no longer than the outer circumference of the holes in the truck. Slip the paper into the holes, like a bushing, then install the sideframe. The paper usually creates enough of an interference-type fit to keep things in place, yet still removeable when necessary.

Wayne

6

Thanks to everyone who replied. This advice has actually helped me with two locomotives, not just one. I’ve been able to do the drilling and cutting on the chassis for the On30 diesel conversion.

Further to this, my no.1 (a Dunkirk) was also built on an Athearn Blue Box mechanism. This advice has helped me bring it back from the brink of becoming a ‘shelf baby’.

Again, thanks to all.