Wrenn locomotive

Discussion in 'HO Scale Model Trains' started by Mike14xx, Feb 13, 2007.

  1. Mike14xx

    Mike14xx New Member

    Hi. Sorry I haven't posted in a while. On Saturday I went to the Train Expo in Monroeville and bought an engine that I need some help with. It is a BR maroon City of London duchess class locomotive by Wrenn. When I bought it and took it to the test track it didn't want to go. The guy said it just needed cleaning. So I took it to a model shop who serviced it for me. When I tried it at home it still didn't want to move. I tried oiling the joints-still nothing. You can here that it wants to move and when you look at the motor you can see that it is trying to move but its like something is jamming it. So I was wondering 2 things.

    1. Can anybody help me with this problem

    2. Can anybody help me determine its value.

  2. MasonJar

    MasonJar It's not rocket surgery

    Value - no idea.

    General maintenance when encountering a bind in the drivetrain:

    Take off the shell and see if the motor can be adjusted relative to the rest of the drive train. It may be too tight a fit between the gear on the motor shaft and the rest. If that's not it...

    Take it apart to the point where you can remove the motor, but leave the drive train intact. Then determine if the drive train can be turned by hand. If that's not it...

    Check the motor - can it be turned by hand? If yes, can it be turned without a load (i.e. will it run electrically when out of the loco?). If that's not it...

    Try reassembling everything. I hope you took notes and/or pictures during dissassembly...! ;) Sometimes this works - I don't know why, but it might have to do with getting the thing's attention :D

    Got any pictures or other info to share with us so you can get more specific info?

  3. Mike14xx

    Mike14xx New Member


    Sorry no pics. The cable for my camera is missing. I was able to turn the motor by hand and the drivetrain moved but when I put electricity to the wheels which are spotless it acts like it can't move. It will just vibrate and shake a little.
  4. bigsteel

    bigsteel Call me Mr.Tinkertrain

    what kind of current does it use AC or DC thats the way my ho scale trains work on AC.if your sure its on a DC track then it could be a short somewhere.it may be as fine as .010 brass wire or a missing ground.point is youll have to open it up and check for anything is not how it should be.sorry i wasnt able to help much but ive never owned a loco by wrenn.
  5. Mike14xx

    Mike14xx New Member


    Thanks I actually hadn't thought about trying to run it on ac. I will try that.
  6. 60103

    60103 Pooh Bah

    NO AC! It's a DC locomotive.
    My wife bought one for about $100 at the NMRA convention a few years ago. I spent another 25 having it looked at by our local expert.
    It has an odd design: the motor is part of the frame casting - the armature and worm ar mounted vertically. The brushed go through the frame -- one is grounded by the mounting, the other is insulated.
    There is an adjustable bearing at the top of the motor that can be turned by a screw driver; don't do anything to this unless you need to.
    There is a small ball bearing (single ball) at the bottom of the worm shaft -- this was missing on mine and the commutator was a little low for the brushes.
    I think I have an exploded diagram somewhere.
    Our local expert also remagntizes motors. The test for the magnet is a six-inch steel bolt with a bunch of washers and nuts on it -- if the magnet picks this up, it's OK.

    When checking for repair shops, also look for Hornby Dublo as it's the same loco. Look on the BRMNA website for dealers. http://home.ca.inter.net/~brmna/prodser.htm
    Ours pulls a 16-foot long train on a 2% grade, which is all I can do on the layout. These are usually pretty sturdy mechanisms.
  7. Mike14xx

    Mike14xx New Member

    Thanks a bunch. If you do have a diagram can you send it to me? Thanks. It is gorgeous the paint and the decals are mint the box is near mint and comes with all the original thinks ie: the manual, the triang tt coupler conversion kit.
  8. 60103

    60103 Pooh Bah

    Exploded diagram

    Mike: I'll try to attach the diagram, if it's still readable after the compression.
    This is the HD sheet and covers two and three-rail versions.

    (If no good, PM me and I'll send a larger version)

    Attached Files:

  9. Mike14xx

    Mike14xx New Member


    thanks. I will try and send a message.

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