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Detailing an HO P1K RDC for the B-and-M

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  • #1

    Detailing an HO P1K RDC for the B-and-M

    Some people have mixed feelings about Budd's RDC, but for a B&M modeler they can't be ignored. For two decades they provided most or all B&M passenger service, and I've spent hundreds of hours aboard them, dozens in the cab.

    Operating my B&M Eastern Route in a post-1958 era will require at least 10, which puts me in a bind: Nobody has ever manufactured an accurate model of the B&M's most common class, the 1955 order of 42 RDC-1s and 13 RDC-2s. The P1K RDC is good for 6 RDC-1s and 3 RDC-3s purchased earlier, but the 1955 order had cast trucks like the old Athearn shorty rubber-band drive RDC.

    I knew Athearn hadn't shrunk the trucks; I'd used them to re-truck a Hallmark RDC-9 in the course of a major rebuild. But I hadn't minded making the RDC-9 a dummy. Some of my P1K RDCs can be dummies too, but I'll need several which can run alone for non-rush hour service.

    More in the next post.
    James

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  • #2
    The P1K trucks came apart after some careful prying with a small screwdriver. The Athearn trucks came from a $10 dummy (more than I paid for my first motorized one in 1968) bought at Greenberg's last weekend. They were pressed and staked together, so it took more prying and gentle hammering to get them apart.



    Here's the proof of concept - with care, NWSL 1.4x.3 screws will self-tap in #57 holes in the old Athearn zinc alloy.



    I'm using the P1K bearing plate because Athearn's axles & journals are conical. In our next installment, we'll see if my idea for mounting the sideframes on the gearbox works out.
    James

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    • #3
      Interesting work, I hope it goes together and works.

      Mark
      W,L,&E

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      • #4
        It took a while to get more screws, and then scenery, operation and other rolling stock intervened. But I got back to it tonight.



        I figured out the dimensions of the mounting plate using my calipers - if you can't read them off the photo, I'll copy them in my next post. The plate is .025 x .250 brass, because I had it handy. The pins are .072 brass rod I also had handy.



        After considerable fettling, I will make the next one with the pins right up against the top edge. I also had to file a bevel on the lower side of the pins' ends, so they could get past the locking parts of the clip that also holds the axles in.



        It won't take me as long to attach the next three sideframes. But when I'm done with this RDC, I think I will try to get the attention of someone who does 3D printed parts - the P1K truck is clearly designed to allow for several different snap-in sideframes, and I'm sure at least a few other modelers will want to model phase I RDCs with the later cast trucks.

        There's also the sentimental side - the Athearn RDC-3 I started my HO modeling career with is next in line to sacrifice its trucks for this project. I might eventually need a half-dozen more, which would put a strain on the local train show supply of rubber-band-drive antiques.
        James

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        • #5
          Nice idea on your conversion, looks like fine brass work at this stage. I have a few PK1 RDC's myself so this is good to know James. Thanks for posting your findings.


          Louis L&R Western Railroad
          Pacific Northwest Logging in the East Coast

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          • #6
            Thanks, Louis.

            Making another mounting plate didn't take as long, so I've gotten it to the point of assembling & testing:



            The Athearn sideframes are about .100 thick, so overall the truck is .095 wider than the original. I haven't modified the P1K gearbox yet, but I'm considering a) mill down the back of the sideframe, b) remove a bit from the ends of the gearbox's mounting tubes, or c) ignore the extra width.

            I was expecting the P1K gearbox to work like other delrin snap-together products I've had apart. It doesn't. The internal gears are much narrower than the box and asymmetrical, set to one side of it. The axle gears are also narrower than the box, and just asymmetric enough that orientation matters.

            If you reassemble it wrong enough, the internal gears won't reliably engage with the axle gears. After taking it apart several times, I've got it running ok but much noisier than it was out of the box. I should have marked the orientation of the worm and the position/orientation of the axle assemblies before I took it apart.
            James

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            • #7
              Later in 2013, I completed the 2nd set of modified sideframes, but before I installed them the project got shelved while I dealt with estate matters, setting my Eastern Route up to operate and retiring. But this month's "Unfinished Symphony" photo gallery has me digging into my shelves, and I was doing a "building models and talking to visitors" at the Wenham, MA museum yesterday and today. What would fill 12 hours of modeling time? Drilling lots of #80 holes and making grabirons to fit:



              I tried shaving the molded-on door grabs off the unpainted shell. The results of shaving and trying to spot drill holes over the cast-on bolt locations were iffy enough that I didn't bother doing it on the painted shell.
              James

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              • #8
                Nice work, James.

                I'm interested in RDC's myself, since both Canadian National and Pacific Great Eastern used then in British Columbia.

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                • #9
                  Outstanding.

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                  • #10
                    Looks good James. Did you have a jig for the grab irons, or are they pre made? In any case they look fine!


                    Louis L&R Western Railroad
                    Pacific Northwest Logging in the East Coast

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                    • #11
                      Nice work James. Those individual grabs and hand rails makes all the difference in a model. I'll be watching this one for ideas for when I do mine.

                      I have an interest in these rail cars and have been collecting them a swap meets. I have plans from, I believe it was RMC, an article on converting one to an RDC-4 RPO. That's a project way down the tracks.

                      Bernd
                      New York, Vermont & Northern Rwy. - Route of the Black Diamonds

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                      • #12
                        Thanks, all. Louis, I drilled some holes in clear acrylic to make a jig for the first bend, but forming a drop grab is still a touchy hand operation. That's why the side grab ladder is straight grabs where they should have a drop. These are 'commuter fleet' models, not for publication or a contest. Bernd, my B&M page only mentions the books by Crouse (who has plans) and Duke/Kelley, but Mainline Modeler covered RDCs, with plans, in several issues starting January 1991 and finishing with the RDC-4 in June. The article I had open beside me was AFAIK the first, Nov. 1958 MR (it was the easiest to lay hands on).
                        James

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                        • #13
                          For once in his life, I listened to Ralphie and checked in here. Thank you, Ralphie.

                          I've got a fond spot for RDC's as both the B&O and Reading had their fair share.

                          Anxiously waiting on the next post here.

                          Carry on, James!
                          Chip Stevens

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                          • #14
                            James, I'm glad to see that this month's Gallery prompted some action. BTW, great use of that time at the Wenham, MA museum. :up:
                            Bruce

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                            • #15
                              James,

                              I found the articles. They are in RMC Sept. 1967. Larry Jackman drew up the plans for the RDC-1,2,3,& 4. Then in the August 1987 RMC issue our own Bob Boudreau won the kitbashing award for doing an RDC-4. One of these days I'll get around to building one.

                              Those magazines are probably hard to find. Perhaps E-bay.

                              Bernd
                              New York, Vermont & Northern Rwy. - Route of the Black Diamonds

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