Building a Mopac GP-18 (newest updates on top of this blog)

[peggyrothschild]

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[Joseph Berry]

Charlie,

The weathering is very nice. The truck side frames are excellent…they look slimy!!!

In your research, did you see any GP-18’s with plows on both ends? Just wondering. (I really can’t imagine the MP spending the money…) Your project is quite the inspiration, thanks for posting.

[peggyrothschild]

@garyh wrote:

Charlie,

In your research, did you see any GP-18’s with plows on both ends? Just wondering. (I really can’t imagine the MP spending the money…) Your project is quite the inspiration, thanks for posting.

My next door neighbor was in the MP’s Mechanical Department early in his career and told me they were just applied to the front. He also commented the snow plows didn’t have the doors but a metal rod. I need to look at some photos and see how the rod was applied.

[peggyrothschild]

OK, the part I hate…installing a decoder.
I used aTsunami2 Model TSU-1100 P.N. 885001 for EMD.

Following the instructions on the small fold over sheet that came with the decoder I wired everything up but when I put it on the track….nothing. Rechecked my wiring and couldn’t figure out what I did wrong. Finally called George at Soundtraxx (who models the Mopac in HO but lives out in Colorado in DRGW narrow gauge country) and found out that the P2K GP-18 has the electrical pickup on the same side for both trucks. George said to scrape a place on the opposite side in the rear of the locomotive and solder the black wire there…leaving the red wire from the decoder soldered to the front pickup. So you now have pickup on the left and right sides like a real manufacturer would do. After I did this “…it’s alive…! to paraphrase Dr. Frankenstein.

Called Bill Herbert about his choice of couplers as he’s doing the two bicentennial units and he recommended Kadee 35’s. Got them today and they are the perfect length. Even after adding the snow plow.

One more tidbit. The pickup on the P2K GP’s are terrible so George recommended soldering a wire from the rear trucks to the front on the left side and from the right rail pickup to the rear right truck so all eight wheels are making contact. This made a huge difference in running. Plus I replaced the bronze wheels with NWSL plated ones.

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[peggyrothschild]

Lessons learned
1) don’t apply the handrails until the model is done. I used Canopy glue to attach them – worked great.
2) I sprayed Tru-Color clear for decalling; the area where I wanted to decal became glossy but the details around it looked like they had frost on them. I went over these with Tru-Color thinner and switched to my old standby Tamiya Clear.
3) I didn’t use any of the weight the P2K locomotive comes with, the frame is heavy enough.
4) additional pickup wires on all sides of the trucks improved the performance 100%
5) Since this was an undecorated model, the number boards and plastic lights were a bear to install. I had to cut them apart as individual pieces to get them to sit flush. I then painted the inside of the number boards black so the LED light wouldn’t show through.

It was a fun project. More more GP-18 to go…

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[Joseph Berry]

Charlie,

Great ‘build’ thread!!! Very enjoyable… The weathering on the entire loco really looks like a 70’s Geep 18.
I think I saw one or two that were actually dark blue…but that was after a repaint and the ‘Eagle Buzz Saw’, so I blocked them out of my mind.

Thanks again for posting your build thread. Good info on the decoder install…hopefully, I’ll get my courage up to try another install myself in the near future.

Gary

[peggyrothschild]

The Microscale decal sheet arrived today for the number boards. Sometimes you just get lucky; the five numbers on the start of a row were 19586 so cutting out the numbers were easy almost like I planned it. I painted the number boards Vallejo black and once dry gave it two brush coats of Tamiya Clear. Then applied the decals and fixed with Microset Blue and then red solution. ACI labels were cut from a Hearld King ACI set and glued on the handrailings support. Will add the radio antenna once I find out how they were mounted. The TSU-1100 decoder sounds great. I have one more P2k GP-18 next up just looking at photos to decide which one.

Hope you enjoyed the build.

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[Joseph Berry]

Charlie,

Great luck on the numbers for the number boards.

My favorite part of your project is the “faded blue” effect overall …and all the weathering, with my favorite being the trucks!

Looking forward to your next Geep.

Thanks again for a very nice 1970’s – 80’s project!

[peggyrothschild]

I ran 1986 last night for an hour; most switching in Eldon and Olean just to see if they were any running issues. The axels go through a bronze sleeve and the sleeves all sit loosely in a metal side frames. On one trip, a few nights ago, the locomotive ran great, tonight it would go 4″ to 5″ and stop and restart. Took it over to the work bench and pulled off the covers to the gears and made sure the stamping and bronze parts were all aligned. It’s a pretty sloppy design to begin with. Put it back together and it ran fine. If I continue to get interminent pickup problems I’m going to add .010 bronze wires to the tops of the metal frames so the wires ride directly on top the wheels for additional pickup.

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