Model Railway Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
50 Posts
Discussion Starter · #1 ·
I have a couple of old triang Locos, they dont run very well through my peco points, Now my question is how easy is the conversion to 3 rail?, as my kids grandfather has an old 3 rail layout in the attic that they use when we visit, so would like to run them on it, the locos are Hymek and Class 37, i have changed the plastic wheels for steel for better current pickup, and the other is the green DMU.
 

·
Registered
Joined
·
90 Posts
Conversion to three rail would require first shorting out the insulation on the pick up side of the loco, if these are older Triang models with the pick-up on both sides of the motor bogie the short will entail a simple connection between the spring on the rear of the insulated wheels and the chassis. Just remove the connection between the insulated wheels and the insulated brush on the motor and connect the wire to the chassis instead. (Bottom drawing)

Then you would need to add a current collection shoe to the underside of the loco. This needs to be insulated from the chassis and wheels and also needs wiring up the insulated brush on the motor.

I'd recommend adding this collection shoe to the non-motored bogie of each loco and replacing the plastic wheels on that bogie to safeguard against short circuits if you have fitted metal ones. In this way the motorised bogie will have pick-ups from the wheels on both sides and the non-motorised bogie will carry the centre rail shoe.

If the loco picks up from one bogie and returns via the other remove the axles from the non-motored bogie and replace them the other way round, this will give you a current return to both rails, albeit from both bogies. Swap the existing wire from the non-motored bogie so that it connects to the same brush as the wheels on the motor bogie then add a new wire from the other motor brush to a collection shoe under the non powered bogie, ensuring that this shoe cannot make contact with the backs of the wheels. (top drawing)

Sorry if this is long winded, either way the electrical connections should be from the uninsulated side of the motor to both rails via the wheels and from the insulated side of the motor to the collector shoe. If the loco is a more recent model with both brushes insulated from the chassis it still requires the same connections from each brush, one to the wheels, one to the shoe.



The collection shoe should be something like that under a Hornby Dublo loco, I'm not sure if you can get spares, if you can that would be ideal, if not then you'd need to make a sprung mounting for the actual rubbing strip so that it makes contact with the centre rail (only) and stays in line with the bogie that it is mounted on. Add some weight in the body over the non powered bogie in order to stop the spring on the collection shoe from lifting the loco off the track.
 

·
Chief mouser
Joined
·
11,775 Posts
QUOTE (dbclass50 @ 14 Mar 2007, 09:44) <{POST_SNAPBACK}>Another option would be to use a Marklin collector shoe.

I believe Roco make one as well.

Regards

John
 
1 - 5 of 5 Posts
Top