The following article describes a project which I much admire. Whilst I am a stalwart of maintaining Poole Farish locomotives as close to their original spec as possible, Richard Deas of The Goods Yard Model Railways undertook a project to re-motor various Farish chassis with Mashima motors. What you read below is reproduced with the kind permission of Richard.
The article is also posted on his rather comprehensive website about Littlewood, a former exhibition n gauge layout.
If you have undertaken any similar projects then please feel free to contact thefarishshed.com and we’d be happy to post your project online. Alternatively, feel free to comment below (your e-mail address will not be published, but is required in order to post).
Instructions for fitting a Mashima LH19 Motor into a Farish Class 37,47,50,52,55 chassis block.
Totally strip down the Farish Chassis
Throw away the old Farish Armature (very satisfying)
Remove the part of the chassis that supported the old motor magnet and brush fixing.
File the two side stretchers slightly to increase the width between them to accommodate the new motor.
Remove the Farish white plastic shaft connectors from the ends of the worm shafts
Connect the new motor to the two worm shafts, I use a small section of class 158 drive spring as this produces a nice tight but flexible joint. Note: the new motor is supported from the worm shafts and is prevented from turning by the proximity of the two side stretchers.
Insert the new drive assembly into the chassis from the top and ensure that the armature is free to turn.
Enlarge the holes in the chassis top plate to clear the motor and fit the top plate, make sure the motor is still free to turn.
Re-wire to suit and re-assemble the rest of the chassis. Make sure you wire the motor so that the loco runs in the right direction.
Place on the track and test.
Notes: The motor can also be installed orientated at 90deg to that shown in the picture above.