All Wheel Pickup
I restore and add DCC to old and new brass steam locos and diesels. After about 200 of these I found the steam engine itself does not usually need wipers. There are enough wheels to pickup power and data packets for the decoder however the pathway to the decoder is not optimized as the model builders do not design nor build for a DCC installation. You must insure the pathway to the decoder is a good metal to metal contact. This requires some serious disassembly of the drivers. If you do this, clean paint from the frame journals. Remove old lubricant. Blow out the axle journals with electrical contact cleaner that id plastic safe ( DO NOT BREATH THE FUMES. WEAR A MASK) and air dry with a can of compressed air. Re-lube these with Neverstall from Daylight Sales. Make sure the driver tires are very clean. DO NOT use alcohol to clean these. Use while mineral spirits.
Make sure the red wire from the decoder to the loco has a clean, solid mount to the loco frame.
Use a reliable micro connector from the decoder to the engine if it is installed in the tender. TCS sells a line of plugs with multiple pin options. For the best connection, hard wire the tender and engine using 30 gauge, copper, stranded flex wire. However your won't be able to pack the engine away in its original box.
For the tender, pickups on both sides of the wheels is a good idea but not necessary if the tender weighs about 4-6 oz. or more. I find a reliable connection can be made if the following is done but the trucks must be removed from the tender and disassembled:
1. Remove burrs and polish the truck frame bolster and mating tender bolster. This is to optimize truck rotation and does not improve electrical. That is done in step 2.
2. Solder pickup wires (30 gauge, stranded flex wire) from the truck bolster directly to the decoder. Remove the trucks. The wire will be soldered to the top of the bolster out of sight when assembled. The attachment point must not interfere with truck or axle movement. Make sure the tender bolster brass is very clean and use a hot iron( 40W) to tin the bolster.and while the solder is puddled, place the pre-tinned wire end into the solder. Drill a pass through hole out of sight in the tender frame. De-burr this to make sure the wire insulation is not cut. Touch up the bare brass with a matching paint.
3. The tender axle journals are often not clean or uniform in shape. This makes for a bad connection. I drill these out with a drill that is .005 larger than the journal. Do not go deeper than the existing hole. After drilling, blow out shavings and clean the journal with mineral spirits. Lube the journals with Neverstall. Make sure the axle ends are clean. Re-assemble the trucks. Make sure all wheels touch the rail surface. Use a surface plate ( granite counter top, piece of heavy glass) and try to lightly pass a sheet of copy paper under the wheels. It should not pass under any wheel. If the paper passes under any wheel it is not touching the rail. Twist the truck frame slightly until all wheels touch.
4. Polsih the tender wheels if these are oxidized, the plating is worn or the pitted. Use a Dremel at mid speed with a buffing wheel and Flitz polishing compound. Micro Mark sells this. Clean the Flitz from the wheels using mineral spirits.
5. Re-assembel the trucks and install to the tender. Make sure the insulated wheels are on the right side of the tender and opposite to the insulated wheels on the locomotive.
Good luck.
