MRC 2-8-4

Discussion in 'N Scale' started by RGW1, Dec 16, 2013.

  1. RGW1

    RGW1 TrainBoard Member

    I just received A MRC 2-8-4( plastic rods) In the mail today,my plan is to convert it to a dummy to run with some Daulmode decoder steam. It actually looks much more detailed than the old Atlas 0-8-0s ,2-8-2s and 4-6-2s. I plan on not damaging any thing so that it could be converted back to a running model.
    I have checked spookshows site ( great help) but how good do these engines roll and does any body have any tricks to improve the rolling quality. I hope to state working on this project soon.

    thanks RGW
  2. randgust

    randgust TrainBoard Member


    Well, lets make sure we're all talking about the same thing here... First version shown with the large, white-end can motor and plastic rods? (original MRC?)


    Disclaimer: I don't have one, only have worked on them, and have an LL 2-8-4 first-run.

    The basics are that you've got to at least remove the worm gear, motor, and the tender pickup wipers, but even after you do that, you've got a big piece of cast metal and a whole lot of moving parts you're going to try to push around (or pull) with another locomotive. Most mid-size/large steam doesn't have enough tractive effort by itself anyway, so using up what you've got to drag another one around really cuts down on the end result tractive effort.

    I don't know...seriously... in order to make this work anywhere near right, you need to remove a lot of weight and parts, and on that frame that's a destructive and non-reversible process. If you've got one that already runs halfway decent (no real damage, missing parts, etc.) consider yourself fortunate and keep it a runner. If you want to doublehead and need help with decoders and speed matching there's a lot of talent here to help. If you've got one that already has a fried motor or something, well, it's a little better than trashing a true classic in N.

    The way it is wired and built makes DCC conversion interesting; can't see from the photo how the one side of the motor is connected to the frame and would have to be isolated. But I'm sure there are those here that have done this already and there's plenty of room in the tender.

    The closest most of us have come to this is either tender-drive back into to boiler or a tender-drive with a free-rolling front end, which is not entirely unknown particularly in European designs. Getting this old bird to really free-roll (I remember gears between all the axles, correct - "Spur gears connect all drivers in proper quartering relationship"?) would be a challenge. All those designs had to include at least one idler between the axles, so you're rolling 8 drivers plus another three idler gears inbetween for rolling friction. I don't 'think' there are pickup wipers on the drivers themselves though, just the tender axles.

    The other obvious 'gotcha' is the flanges, if you're thinking Atlas C55 you have a problem right there. Should be OK with Peco C55, it's these old birds that keep that design viable if you don't want to turn drivers and other wheels down. The LL 2-8-4 has far smaller flanges, but I guarantee that MRC will outpull it.

    Bottom line here for my analysis is that if you really want it, the effort to simply convert it to DCC now is less frustrating than trying to use it as a dummy.
  3. Kenneth L. Anthony

    Kenneth L. Anthony TrainBoard Member TrainBoard Supporter

    A comment unrelated to the model modification question, but remotely reminiscent of the prototype. Thirty-five years ago, I had to find someone's address, heard they lived on Burkshire Street (spelling different than "Berkshire" but still made me think of the big NKP 2-8-4.) Okay, Mister, what is your house number on Burkshire Street? He told me it was 759 Burkshire. Did I get it written down, he asked. Nope, no need to. As a train fan who had seen so many models of NKP Berkshire #759 in so many scales, I didn't need any help in remembering the address.
    759 Burkshire?!?!?!?
  4. RGW1

    RGW1 TrainBoard Member

    I know pulling a large steam loco dummy is hard work.I have a Trix K4 that can be pulled but sucks up alot of TE. This engine looks nice,I think I may keep it a runner. It is the MRC sivler motor plastic rods. just missing the front truck.
  5. RGW1

    RGW1 TrainBoard Member

    Just tested it with wire leads, seems to run good. Decided not to make a dummy. I have a new atlas slow motor from a I beleave SD60 (ordered wrong motor) does anybody know if the motor shafts are the same? I plan on getting some 3 axle bachmann spectrum tender truck for improved pickup.
  6. randgust

    randgust TrainBoard Member

    Pilot truck of the locomotive missing or front truck of the tender? Note that brass locomotive parts still seem to show up regularly on Ebay, you never know.

    Not sure how familiar you are with maintenance, but recommend a synthetic lubricant like LaBelle 108, just go really, really easy on that stuff around the end of the motor with the brushes, if overlubricated it can make one awful mess inside a motor. The heavier LaBelle is good for brass gears.

    Most motors like that depend on precise case fit in the cast frame to get the tolerances right between the worm and the worm gear. There is likely no front bearing on the motor shaft into the frame itself. Swapping motors, while not impossible, can be pretty limited on options and may require some real work at some real risk because you have to drive the worm off of the existing motor to get it on the new one. If you've got the right tools (including a "V" shaped steel tool to support the worm while tapping the motor shaft out) it's doable, and it is possible to drill worms for a larger shaft, it's going the other way that gets really difficult.

    The Atlas slow-speed is an excellent motor but may be a real challenge to mount properly. But I'm glad to see you're not gutting it. That's really the locomotive that launched N scale for a lot of people and got the attention of real modelers everywhere.
  7. RGW1

    RGW1 TrainBoard Member

    I will run it first with the stock motor and maybe a Bachmann spectrum tender wired direct to the motor.I have along main line run if it runs good at a scale 30 -50 mph I will leave it with the stock motor.Can't seem to find spectrum 3 axle trucks so I will have for now a 2-8-4 with a smaller tender and leave the mrc tender along. The part I am missing is the front engine truck,but I think I can make another one work.

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