Class 24/25 Final Assembly

Take one of the drive units and match it up with its wheelsets. Apply grease (either silicone grease or a general purpose grease suitable for use with plastics) to the unit's gear teeth, and lubricate the worm shaft bearings with a light oil.

Orientate the drive unit with its bogie subframe; with the drive socket facing towards the inner end of the bogie. Check the identification marks on the bearing carriers with reference to those on the bogie subframe and clip the wheelsets into position in the drive unit. Check that the drive mechanism turns freely by hand.

Fit the drive unit into the subframe. Ensure that the four bearing carriers are correctly engaged in the slots in the subframe.

Drive unit and primary springs fitted Thread the primary springs into position on each side; through the inner stretchers, the inner bearing carrier, the traction ear, the outer bearing carrier and, finally, the outer stretcher.

Bolster and Secondary Springs fitted Take the bolster matching the subframe and orientate it correctly, with the face of the bolster tower which is set back from the bolster base facing towards the outer end of the bogie. Place the bolster over the subframe's traction ears and fit the secondary springs. Route the pickup wires through the holes at the top of the bolster.

Sideframes fitted Fit the bogie sideframes.

Cardan shaft fitted Find the cardan shaft and clip the correct end into the drive socket of the bogie.

Remove the retaining screw and sleeve from the top pivot of the bogie.

Fit the bogie back into its end of the chassis block. Start by routing the pickup wires through the appropriate holes or slots in the block. As you do this, manoeuvre the bogie into place; the bolster tower goes in forward of the narrowed part of the aperture to start with, to clear the pickup wires at the top of the bolster. Engage the free end of the cardan shaft into the loco's flywheel drive socket and line up the bogie top pivot with its pivot hole. Take up any slack in the pick up wires as you go. Finally, fit the bogie retaining screw, sleeve and washer.

Repeat all of the above for the other bogie.

Connect the pickup wires to the correct terminals of the loco's PCB.

Place the locomotive on some track and give it a test run under power.

All being well, that's it! - the modifications are complete.

Run the locomotive in, gently at first. If the loco does not run freely or begins to bind up at any point, pay particular attention to lubrication of the axle bearings. You can feel for any binding by rotating the wheel rims with the fingers - there is enough slack in the drive train gears that you should be able to distinguish between a binding and a free wheelset.

Finished! Finally, replace the body of the locomotive according to the manufacturers' instructions.

IMPORTANT NOTE: If you need to remove the body subsequently, it is best to avoid pulling on the bogies when separating the body from the chassis.