Building a Mopac GP-12 1065 (ex M-I RS-3)

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  • July 14, 2018 at 4:05 pm #6123
    peggyrothschild
    Participant

    Bachmann has a nicely done Alco RS-3 with DCC/Sound that you can find for around $100 on eBay or Amazon you could probably save a little money and buy their DCC only version as the decoder will be replaced with and EMD 567 12 cylinder decoder. Lots of model companies made the early RS-3; Atlas, Athearn, Bowser, Roundhouse, MDC, Kato and Stewart made the three different versions so they are easy to find.

    I’d always shy’d away from modeling one of these unique Mopac conversions (MP removed the Alco 422 primer mover and replaced with a EMD 567 12 cylinder from their retired E-8’s) due to the MP having Phase III carbodys. I then came across a photos of the M-I RS-3s with the Phase I carbody that were also converted to the GP-12 so the conversion was dueable. I’m still gathering parts (they are scattered in the text) but here’s a collection of photos to get anyone else involved with this project.

    The Bachmann model is easy to take apart; unscrew the fuel tank and there’s two screws holding the carbody. Then unscrew the two couplers and remove them and the carbody lifts off. I soaked the shell in Scalecoat ‘Unpaint’ overnight and the paint comes right off I’ve also had luck with 91% rubbing alcohol from Walgreens as a paint remover on Bachmann carbodies. The crew cab is a little tricky to remove from the shell; there are four small tabs in the walls and four in the floor. I merely carved these off from the inside and the cab lifted off. I then used a flat Exacto blade and removed the cab windows for painting later.

    [attachment=1:rxwbwuvf]C51F2B02-D358-4858-A89F-792D0523CED4.jpeg[/attachment:rxwbwuvf]
    [attachment=4:rxwbwuvf]fullsizeoutput_a9e.jpeg[/attachment:rxwbwuvf][attachment=3:rxwbwuvf]P7iV6+lCTO2XcoefFio4CA.jpg[/attachment:rxwbwuvf][attachment=9:rxwbwuvf]IMG_0546.JPG[/attachment:rxwbwuvf][attachment=8:rxwbwuvf]fullsizeoutput_a71.jpeg[/attachment:rxwbwuvf]
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    July 14, 2018 at 4:22 pm #8876
    peggyrothschild
    Participant

    More prototype shots for reference; note the early RS-3’s were built with poling pockets whereas the later group built in 1954 with the phase III carbody didn’t.

    [attachment=3:3feav06f]fullsizeoutput_a8a.jpeg[/attachment:3feav06f][attachment=2:3feav06f]fullsizeoutput_a83.jpeg[/attachment:3feav06f][attachment=1:3feav06f]fullsizeoutput_a81.jpeg[/attachment:3feav06f][attachment=0:3feav06f]fullsizeoutput_a89.jpeg[/attachment:3feav06f]

    July 14, 2018 at 11:14 pm #8862
    amosluettgen1665
    Participant

    I’m going to follow your build with interest. I have an O scale brass Key RS2 which I am converting to M-I #960.

    …gregg

    July 15, 2018 at 12:15 am #8877
    peggyrothschild
    Participant

    Just to add to the research on this project; here’s a GP-12 with the two radiator fans both being the type as used a GP-7 or GP-9 and not having the high cowling applied to one. Note to they are placed at a different 45 degree angle than the black and white photograph. So look at your photos carefully when modeling one of these locomotives. I’ve noticed the pilot hand railings have minor detail differences, the placement of the air tanks also can be different depending on the locomotive.

    [attachment=1:18gux58s]8E3EB1F0-BA74-4B99-AD76-C891DB27634C.jpeg[/attachment:18gux58s]

    So the sausage making starts; I have a drill press in the garage so I put in a small drill bit (1/16”) and drilled holes around the Alco fan and then took a sprue cutter and cut from hole to hole to get to this step. You could also do this with a Dremmel tool or even a hand drill. The Bachmann plastic is fairly soft so I used the sprue cutter to remove some additional plastic too. The remaining plastic will be removed using various files. One thing to remember is to save the two number boards as they will be glued back on the unit after the box for the fans is added.

    [attachment=0:18gux58s]DEFCAF57-4D07-4DC2-A12D-97F20044FDFE.jpeg[/attachment:18gux58s]

    July 15, 2018 at 4:30 am #8881
    mopac
    Keymaster

    Gregg this will make a great project in O scale.

    Bill Basden Delta Models http://www.deltamodelsusa.com

    @glaiben wrote:

    I’m going to follow your build with interest. I have an O scale brass Key RS2 which I am converting to M-I #960.

    …gregg

    July 15, 2018 at 5:01 pm #8882
    peggyrothschild
    Participant

    Dressing up the radiator area and shell for adding the box that holds the two fans.

    [attachment=3:3o8mbjjr]1FA4BB58-8597-40CE-BF1B-BC7965130BEE.jpeg[/attachment:3o8mbjjr][attachment=2:3o8mbjjr]226BA1BF-61C9-41E6-9D9F-E31421ACA4AB.jpeg[/attachment:3o8mbjjr][attachment=1:3o8mbjjr]2C412CA3-1197-4CEC-9933-86FEAA911CF7.jpeg[/attachment:3o8mbjjr][attachment=0:3o8mbjjr]34A0AC16-3948-4389-BDC5-817505E101C0.jpeg[/attachment:3o8mbjjr]

    July 21, 2018 at 6:07 pm #8891
    peggyrothschild
    Participant

    The Alco stack is glued on the carbody but comes right off with a little push. Unfortunately the stack sat in a shallow rectangle and the impression needs to be level with the top of the hood. I taped over the rivets on the hatch and spread Tamiya fine putty in the impression. Let it dry overnight and the sand down with medium and fine sanding sticks. Then shoot a light coat of Tamiya Fine primer over the area and dress up any imperfections. Also the carbody has several small details that I think the Chinese couldn’t determine they were Alco loops for lifting the hood so their best guess was the very small detail centered by the stack. Remove these but leave the small circular vent(?).

    [attachment=0:1lj8u2ye]4D0E8753-A918-4ECD-AA72-F61DDEE99CEF.jpeg[/attachment:1lj8u2ye]

    I’m getting to the point where I feel I can build the large box that sits above the radiator. It sides flush with the sides and top of the hood so that will be my guide.

    I’m getting quite a collection of necessary parts to to the GP-12 (tall and lower 36” fans, hand grabs, Plastruct tubing, etc). So contact me if you’re going to also make this conversion and I can help as some of the parts are hard to find or you don’t need a package of four fans when the model only takes one high and one low fan.

    July 25, 2018 at 6:31 pm #8898
    peggyrothschild
    Participant

    I decided to make the GP-12 fan box out of two .010 pieces and three .040 pieces of Evergreen styrene stacked together and glued with Tamiya Thin glue. This creates a strong plastic ‘box’ that can be sanded. I’ll use Tamiya putty to smooth out the sides and corners. Just a side note I ended up making two of these parts with the first one being gently tossed into the waste basket as the sides were too rough and out of square. Once I had a pattern it was easy to make a second one.

    [attachment=4:3bfpityg]798CE493-42B8-425C-8777-E17C8B65E1C7.jpeg[/attachment:3bfpityg][attachment=3:3bfpityg]221B811A-6A51-402C-9416-37DF5B397FBF.jpeg[/attachment:3bfpityg][attachment=2:3bfpityg]1CF80D4C-C896-44CC-B674-A07FDA96E393.jpeg[/attachment:3bfpityg][attachment=1:3bfpityg]1F97013B-47E9-4E5A-AA9B-4A192F3FC0C6.jpeg[/attachment:3bfpityg]
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    July 27, 2018 at 5:55 pm #8901
    peggyrothschild
    Participant

    I sanded on the plastic box until it was flush with the rivet strip above the louvers and glued it in place. The two fans aren’t attached yet; I need to make an oval .010 plastic piece for them to sit on first but you can see the GP-12 is slowly emerging 😯

    [attachment=2:2aeozmq8]508B432A-C424-4AEA-8F4D-D7CB82DD28D8.jpeg[/attachment:2aeozmq8][attachment=1:2aeozmq8]BAFFC6AA-AC95-4D5F-A80F-CCF411AE1C73.jpeg[/attachment:2aeozmq8][attachment=0:2aeozmq8]5B31A0D7-E96F-4C9A-8390-5AA23AB593C2.jpeg[/attachment:2aeozmq8]

    July 27, 2018 at 11:16 pm #8902
    amosluettgen1665
    Participant

    Looking good!

    …gregg

    July 28, 2018 at 1:00 am #8903
    peggyrothschild
    Participant

    We’re about 1/3 into this project. Lightly sand the roof of the cab as there’s a circular mark on top. This will later get the firecracker antenna, glue in the four windows in the front and back walls since the Mop painted these over and sand down the headlight casting on the noses as this will be later plugged with a plastic inset and putty and a Detail Associates LT1012 headlight casting will be used to match the prototype. Hopefully will cut out the oval for the fans to sit on and add Acher rivets to complete that part of the model. Second phase will be adding the muffler, stacks and spark arrestors and the final phase painting, decals and weathering. [attachment=1:2gue6itl]3973039E-7BC5-4827-8362-B3DD4379AAFD.jpeg[/attachment:2gue6itl][attachment=0:2gue6itl]00599A84-25AE-4355-83FC-00797F0294A2.jpeg[/attachment:2gue6itl]

    July 28, 2018 at 7:19 pm #8906
    peggyrothschild
    Participant

    Adding the fans:
    I have a metal triangle that has several different size holes cut in it and found a circle that matched the metal plate radius I needed. I first made up a paper template and used this to get the length of the piece and taped it. I then used this on a piece of .010 Evergreen sheet plastic to make the final piece. Initially I cut it out with a scissors and then dressed it up with a medium sanding stick. Once I was pleased with its location I glued it with Tamiya thin cement which leaves no residue. The two 36” fans were glued down and the front one received a collar using Detail Associates FA2001 (F2/F3 high fans). The inside of the fan was removed leaving only the circular plastic collar and this was sanded to make the walls thinner. Archer rivets will be added to the plate later.

    [attachment=4:1fg25f6j]6C5D4C30-8A83-4F81-A557-1C382F64F18F.jpeg[/attachment:1fg25f6j]

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    Take some .040 styrene and cut two circles out and plug the headlight openings glue with plastic glue and reinforce with acc glue and putty to hide the seams.[attachment=1:1fg25f6j]EBF1A7D1-E138-43BD-803D-2718D42CB3EB.jpeg[/attachment:1fg25f6j]

    July 28, 2018 at 10:52 pm #8907
    peggyrothschild
    Participant

    This open grill work doesn’t appear on MP or M-I units or at least in the photos of the GP-12 overhead shots. Part of this area will be hidden by the exhaust arrangement but not the entire grill. I’ll either cut this area out and replace with sheet plastic or fill with putty. Putty is faster but it’s difficult to not sand off the details. We’ll see how industrious I get. Well as you can see this area was cut out. Putty requires a couple of applications due to shrinking and then one has to be careful not to sand off any details. I’ll file this area and add a piece of plastic as a plug.
    [attachment=1:3c26jr81]33E90770-FD66-472E-8B49-84E9370A8CC6.jpeg[/attachment:3c26jr81]
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    July 29, 2018 at 3:27 pm #8909
    peggyrothschild
    Participant

    Page 45 in Jim Boyd’s MP color book volume 2 shows an overhead shot of 965 which verifies the center area was not a grill as on the model. I added a piece of .040” plastic in the opening. Looking at photos the MP mechanical department made a shorter panel when the Alco stack was removed and the locomotive was rebuilt for the EMD engine. I’ve shown this the hatch by the pencil line going across the hatch on the model. Initially I thought of ignoring it but I’ve made enough changes already why quit now? The other two shorter pencil lines are for determining the length of the exhaust. The shorter hatch clearly shows on page 47.

    [attachment=2:1wjv4bjr]03FA1859-FDB1-4E8A-9D31-264F48FC120A.jpeg[/attachment:1wjv4bjr]

    Main exhaust piece was cut out of Plastruct tubing and the ends capped with .010” plastic. I basically guessed at the length and height using the side doors on the hood and the overhead shot in Boyd’s book. I also shortened the hatch towards the two fans.
    [attachment=0:1wjv4bjr]1199108F-E73D-41A2-B003-C218BD5C4A52.jpeg[/attachment:1wjv4bjr]

    July 29, 2018 at 7:54 pm #8911
    peggyrothschild
    Participant

    The cast metal spark arrestors are a little taller than those used on the GP-12s but no model is perfect (at least not mine). Prototypically the spark arrestors sat on an upside down ‘|_|’ metal frame which the exhaust stack fit through. To simulate the frame I cut six Evergreen 1” x 10” pieces and acc glued these to the bottom of the casting getting the plastic flush with the outside of the spark arrestor. I still need to make the exhaust piece wider.
    [attachment=4:tu7jdl2d]0EA1C5EB-0B37-45E8-9405-547ABEFBAB20.jpeg[/attachment:tu7jdl2d][attachment=3:tu7jdl2d]33C54E79-116F-4DD1-A350-B5048F792F98.jpeg[/attachment:tu7jdl2d][attachment=2:tu7jdl2d]7ACEE26B-1071-4D36-B80E-11F65A08FA7D.jpeg[/attachment:tu7jdl2d][attachment=1:tu7jdl2d]5F205EA5-4AB3-4F56-9917-9A7DD4797846.jpeg[/attachment:tu7jdl2d][attachment=0:tu7jdl2d]12DF96ED-7B19-41F0-A95A-D9846C41C02E.jpeg[/attachment:tu7jdl2d]

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