The unit you have received is to be fitted into the Bottom Plate and the Chassis must be opened up to accept the larger motor of the new drive unit (Section III). To ease the modifications, detach the Cab/boiler superstructure by unscrewing seven screws and freeing the pilot braces from the smokebox.

The first modification is to the Bottom Plate. You removed this plate when you sent in your wheels, see Appendix A & B. The first step is to free the Bottom Plate from the Chassis. The screws holding the Bottom Plate to the Chassis should be removed. There are two wires from the pilot truck which need to be cut at the motor posts. These wires are usually brown and black. The reason for cutting them at the motor posts is to give you the maximum amount of wire for later wiring. Do not cut the two pink wires. If all of the wires are cut from the motor posts -no problem. Free the brown and black wires so they can be pulled out of the Chassis (usually there is some yellowish hard cement securing the wires to the insides of the Chassis, use a hobby knife to detach this cement). Set the rest of the loco aside and place the bottom plate on your workbench.

Compare your bottom plate to the picture in Appendix A. The first cut will be to the section carrying the hook to the tender (we'll call this the "Hook Section"). This is the easiest cut. The exploded view shows where the cut is to be made. Scribe where the cuts will be made. Cut each of the sides, before cutting across the bottom. After cutting, sand the cuts smooth by placing a piece of fine sand paper on a level surface and sanding the face of the hook section on the sand paper until it is smooth. This piece will be screwed in place to the rear of the unit, so the smoother the better. Once smooth, the hole is drilled to accept the screw to the rear bulkhead. Cut out and place Template A on the rear hook face, tape in place (the hook point is down) drill a 1/8" hole through the template and the face of the hook unit.

The second cut (the "Pilot Section") is similar to the first and cut in the same manner, see the exploded view in Appendix A, with the addition of the existence of two fillets which need to be cut and smoothed, as above. Scribe where the cuts will be made. First cut the sides, then cut the bottom from one side cut to the other side cut as straight as possible. This should free up enough space to force the razor saw inward to cut the remains of the fillets (or a side cutter can be used to cut the remains of the fillets). Sand the face of the Pilot Section smooth. Place and tape Template B on the face of the Pilot Unit and drill the 1/8" hole, as above, then cut the lower section away.

Remove the screws from both endplates of the BBT DRIVE 460 unit. Insert one of the screws into the rear Hook Section from the recess side. Insert this screw into the rear bulkhead of the drive unit. Tighten the screw, squaring the Hook Unit with the drive unit (If you cannot square the unit properly, elongate the hole). This will be the most difficult screw to tighten in this whole operation, because of the angle involved. Insert the second screw into the new hole in the pilot unit and attach to the front of the drive unit, keeping the pilot unit square with the drive unit frame.

The BBT DRIVE 460 provides a new method of mounting the Pilot truck. The modifications to the pilot are in Appendix G. Make the modifications and attach the pilot truck to the tongue projecting from the Drive Unit. A section of shrink tubing is provided for the wires, thread the pickup wires through the longer tubing, route the tubing up through the crescent-shaped opening in the pilot section of the Bottom Plate. Or a 3/16" hole can be drilled just in front of the plate attaching hole.

This is the most convenient time to check the polarity of the pilot's pickup wires; i.e., which of the pilot wires works with the drive wires without a short. Ensuring that the pilot truck is in it's forward position, re: arrow on the bottom of the pilot, place the drive unit with the pilot on a powered section of track. The drive unit has two wires which lead forward and do not have their ends stripped. Strip 3/8" of the insulation away from each of these wires and the same to each of the pilot truck wires. Twist one wire from the drive unit to one wire from the pilot truck together (do not solder), repeat for the other pilot truck wire. Apply power to the section of track, if the unit moves forward or backward, make a note of which wire is attached to which wire. If the unit does not move, it is short-circuited, swap the wires and it should then move. Make a note of the match.