I learned in the West Coast NG about the GP60M used as a switcher and transfer engine by BNSF. BNSF used the GP60M for transfer runs in the LA area to feed the LAJ. Athearn has a nice looking model of the GP60M but.... it has the "usual old" Athearn RTR motor.
So beautiful but such an ugly noise. Looking around on my shelve I noticed the GP40 looks similar. The same quite short trucks, similar over all length and it is an Atlas FEC engine with a great drive.

It was extremly easy to make the Athearn shell fit on the Atlas drive. Some plastic under the cab and under the hood has to be cut out. No photos or further explanations needed. You will see immediately what needs to be cut. The shell is mounted with the Kadee coupler boxes of the new whisker couplers. Couplers are #156 (long whisker) because the Atlas coupler mounting hole are a little bit to far away from the end of the engine. But no problem. It still fits to hold the shell and couple without problems.

Some flat aluminium paint (Tamaya XF-16) on the trucks and lower part of the visible body and a silver spray from the can for the tank completed the finish.

The engine runs great!!

Ok, what is missing? The lamps are not working right now. Atlas uses SMD LED and Athearn the usual bulbs. I did also run the bulbs with a 1kOhm resistor on my DCC decoders in the CF-7 engines but how does that match the Atlas LED current? Do you have experience how to attach Athearn bulbs to Atlas LED circuits? In worse case I would rewire the bulbs with resistors to the white/yellow and blue wire of the decoder bypassing all Atlas logic.

Great work. Is there any way to modify the old Athearn sideframes to fit? The reason I ask is that the GP60M had a slightly different sideframe than the GP40 (Blomberg "B" on the GP40 versus Blomberg "M" on the 60 series). What is causing the front steps to droop down? Is that fixable?

Tom Wrote:Great work. Is there any way to modify the old Athearn sideframes to fit? The reason I ask is that the GP60M had a slightly different sideframe than the GP40 (Blomberg "B" on the GP40 versus Blomberg "M" on the 60 series). What is causing the front steps to droop down? Is that fixable?

The drop down front steps were caused by a too tight screw of the front coupler. I fixed that.
The trucks are even more complicated. I did convert a second engine and used my second FEC GP40 for that. Looks like Atlas has two version of FEC GP40 on the market. While the first one (on the photo) has SMD LED and only the inner breaks on the trucks has the second unit standard LED and breaks on both sides of the axis. Looks like they are complete different trucks. The Atlas web site offers only a GP38/40 truck. That must be the longer one (left on my photo). I do have two SP GP40. They have both the shorter trucks (right on the photo).

This pdf file shows both trucks used by Atlas for the GP40 http://www.atlasrr.com/pdf/PartsPDFs/HO_...Page_2.pdf

I did not try to exchange the Athearn and Atlas truck side frames. I do not want to tinker with the perfect running Atlas drive.

Second unit on the left, first converted unit on the right

The shorter trucks are only shorter because they lack outboard brake shoes. They also have a strut on the right journal. this makes them Blomberg "M" trucks and are correct for the GP60. The trucks on the left are the older "B" Blombergs, have outboard brake shoes, and are not correct for a GP60. But they look better if you ask me.

Nicely done on the conversions.

Dave

I agree they look better, but I stand corrected (and apologize) in the first photo, your #139 DOES have the correct Blomberg "M" truck, what threw me off and made me think it was a Blomberg "B" was that it was missing its front strut, and the "M"'s usually found under GP59/F59 and GP60's have exposed roller bearing caps. So yeah, you had it right the first time, sorry about that.

I will see if I can get a pair if Blomberg M trucks from Atlas for the second unit. The part numbers are somewhat confusing. Have to dig into that.

The lamp story is finished. I did use my standard 1.2 kOhm resistors per Athearn bulb. That is a save value that works fine direct at the decoder wires and it works also fine on the Atlas board. Atlas has some advanced mimic other than a simple resistor to have constant lights.

I learned in the Atlas forum that the GP40 frame is about one foot to short. That is true but I am still happy with that wonderful silent running (to short) GP60M

I did it again


Athearn sells an RTR SD40 in the colors of the PHL. there are two small problems
a- PHL has no SD40 but a MP20C-3 based on SD40.
The guys over at the West Coast Forum provided a nice photo ( http://www.westcoastrailforums.com/attac...?aid=13441 ) of the roof. The turbo exhaust stack has been closed and two pipes have been installed. That is the most significant change visible to everyone. The other changes are minor and will be skipped to save the perfect finish of the shell. The prominent air condition is on order.

b- Athearn RTR drives are not my favorits
Kato has a nice drive that fits with some milling on the drive and the shell. It is about 1.5mm to high mounted but the overall impression is still ok. I had to extend the holes of the couplers to mount the shell.

Next invisible step is the replacement of the PCB with a home made to add resistors for the Athern mini bulbs. The Kato LEDs are useless with an Athearn shell and fix mounted mini bulbs. The "Athto" engines is beautiful like an Athern and runs smooth like a Kato

1K resistors would be correct for runnign the LEDs. I repalce the bulbs with LEDs when I install DCC in all my locos and just use a 1K resistor, Results in about 9-10ma to the LED, they can take 20-25, so it lights up plenty bright but with plenty of headroom in case of some other fault that might increase the track voltage.

--Randy