Heljan Class 35: Final Assembly

Fit drive unit to subframe Orientate the drive units, with universal drive couplings facing the inner end of each bogie, and slot each unit into its subframe. Ensure that all the bearing carriers are correctly engaged in their slots in the subframes.

Primary springs fitted Re-fit the primary springs, and check for free vertical movement of the axle bearings in their slots.

Bolsters refitted Re-fit the bolsters to their subframes. Check that there are no short circuits between the etched bogie components and the pickups.

We now re-fit the bogies to the loco. The procedure is described in a little detail as the clearances during assembly are quite tight. If you find that you can not engage the drive shafts in the bogie couplings, you may find it helpful to remove the pivot frames, refitting them once the shafts are in place.

Drive shaft inserted in flywheel socket Insert the drive shaft for one of the bogies into its socket in the flywheel.

Bogie introduced into aperture From underneath the loco, offer up the bogie into its aperture in the chassis block. You will need to get the bogie as far forward as possible in the aperture, making sure that the pickup wires are not trapped.

Fitting the free end of the shaft to the bogie coupling Push the top of the bolster towards the outer end of the loco as far as it will go, and spring the free end of the drive shaft past the bolster into the space within the bolster arch.

Spring the free end of the drive shaft into its socket on the drive unit. You will need to lower the bogie within its aperture, and lower the drive shaft to touch the floor of the chassis block, to make this possible. Once the shaft is engaged in the socket, bring the bogie fully up into position.

Check for free rotation of the motor shaft and correct location of the drive shaft.

Align the holes in the bolster top and pivot frame. Insert the insulator, washer (if desired) and pivot screw and tighten the screw to secure the bogie.

Repeat for the installation of the other bogie.

Applying thread locker Place the loco on its wheels on a flat, level surface. Remove the two pivot screws, washers and insulators.

Using a cocktail stick or thin wire, introduce a drop of thread locking fluid into the captive nuts at the top of each bolster.

Bogie fitted Refit the insulators, washers and screws. Tighten the screws until there is just a very light preload between the bolster top and pivot frame. You are aiming for a setting which allows the bogie to swivel freely (important), but prevents the bolster from rocking in the frame (less important).

Give the thread locker a little time to set.

Circuit board reseated Re-seat the circuit board into its rubber clips, and plug in the connectors to the bogie pickup wires.

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

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 gears that you should be able to distinguish between a binding and a free wheelset.

All being well, thats it! - though you might still have the sideframes, and maybe the optional brake bits, to fit if you postponed that from earlier.

Finally, replace the body of the locomotive.

IMPORTANT NOTE: If you need to remove the body subsequently, please DO NOT at any stage attempt to pull the chassis from the loco by pulling on the bogies, as this may damage the secondary spring mountings.