Converting a Brass Locomotive to DCC

I have a love of steam locomotives and it's perhaps natural that his interest should gravitate to brass engines.  I like the details and weight of brass locomotives and also look forward to the challenge of restoring them to excellent running condition and converting them to DCC and sound.  Inspired by an article in Railroad Model Hobbyist on installing replacement motors and gearing, I decided that making such conversions is probably within my ability, even though I've never done one before.

I located a suitable subject for conversion on eBay: a Pacific Fast Mail Tenshodo USRA 0-8-0 that he would like to see operating in the yard of the North Fork & Crooked Run Railway.  This engine was unpainted and the electrical connections to the motor were severed.  The coal load, which had been added to the original model, was partially missing.

The PFM Tenshodo USRA 0-8-0 in its original condition

The first task was to build a cradle to hold the locomotive, and others to follow, upside down for disassembly and repair.  I had some surplus walnut left over from another project and, using pocket hole screws, made a U-shaped device 15 inches long.  To the sides of the U, I stapled a piece of cloth draped into the well of the U so it would hold a locomotive at a height convenient for working that would safely protect the locomotive's details.

Then I tested the conductivity of the locomotive with an ohmmeter.  The drivers proved to be insulated, an essential criterion.  Had they not been insulated, the whole project would have had to be scrapped, as replacing the drivers would have been out of the question.  I got good conductivity from the drawbar to the motor wire, on the other hand.  However, this was not really important, as the motor is slated for replacement.

The next step was to remove the boiler and tender shell.  The boiler is held in place by a large screw through the steam chests and two small screws located at the back of the cab.  Four screws hold the tender shell to its frame.  I removed the tender wheels at the same time.  I had purchased a plastic box with dividers to hold the parts from the locomotive, and as I removed these, I placed them in individual compartments with a label to remind me what they are.

The disassembled USRA 0-8-0

I then evaluated the motor's ability to power the disassembled drive train.  It operated only haltingly and then only when I put hand pressure on it.  Clearly, it was a candidate for replacement.  The original motor was an open frame type.  Experts in this field call for replacing these originals with can motors.

The original open frame Tenshodo motor failed to function and clearly needed replacing

The gearbox was also found to have a lot of slop in it and I decided it too needed replacing, as did the coupling mechanism.  These imported brass locomotives used a piece of rubber tubing to join the motor to the gearbox.  The tubing had enough flexibility to accommodate movement in the gears during starting and stopping movements.  But over time, they stiffen up and can even crack, thus losing their ability to transmit power to the wheels.  The recommended practice is to replace this linkage with a dogbone style coupling.

The original gearbox had a lot of play in it and it and the coupling mechanism were clear candidates for replacement

I then measured the interior size of the boiler and tender to determine the sizes of parts that could be fit into them and ordered parts for upgrading and restoring the locomotive.  Based on the measurements and my own intentions for the restored model, I ordered the following parts:

From Osorail, the following North West Short Line parts:

• A 36:1 idler gearbox with ball bearings; this will make the switcher run a little more slowly than the 28:1 gearbox, and the ball bearings will help it run more smoothly
• A 16mm flywheel
• The 2032D-9 flat can motor
• Axle stock and shaft universal connectors

I also ordered some tools to help ensure accurate and precise installation of parts:

• The Sensipress to press together wheels and gears
• The Quarterer, to assure that the drive wheels are properly quartered
• The Aligner for 3mm axles to enable precise wheel and fear alignment

I probably would not have purchased these tools for a single locomotive, but I have in mind converting others in the future and it made sense to have them available for the first conversion to help it go smoothly and accurately.

From Yankee Dabbler, via eBay:

• The Soundtraxx Tsunami2 TSU-2200 2 amp sound card for steam engines which contains a large variety of steam locomotive and whistle sounds, among other effects, and which incorporates DCC capability so a separate DCC card is not required
• The Soundtraxx Current Keeper, which contains a capacitor to keep power to the locomotive even when it's passing over dirty track with poor conductivity

From Tony's Trains:

• A TDS high bass 28mm speaker
• A TDS speaker enclosure

While waiting for these parts to arrive--and the time to install them--I cleaned and painted the locomotive and tender.  I'll address that in a future posting.

Norm