East of the Blue Ridge

Chronicles of an On30 quarry railroad

June 2011

Module Mogul - 2

Adding sound to a model locomotive puts a premium on electrical contact.

Intermittent breaks in the current flowing from the rails to the locomotive are always aggravating, and a sound system only accentuates these lapses to the point that they can become infuriating. I followed Harold’s advice and added electrical pickups to the Mogul’s tender trucks, but I did not do it the same way he did.

I found electrical contacts to the tender trucks to be somewhat difficult. The tender balances on the center bolsters of the trucks as they swivel and rock along the track. Adding electrical wires running up from the truck wheels into the tender interferes with the balance of the tender and restricts the movement of the trucks.

I decided to add only one set of pickups to each truck. One truck would pick up power from the positive rail, and the other from the negative.

The electrical contact scheme I eventually settled on was to use Kadee phosphor bronze coupler centering springs as wipers making contact with the inside of opposite pairs of wheels in each truck.

Leads were soldered to the Kadee springs, threaded up through holes in the floor of the tender, and connected to the Tsunami sound decoder. A qualified success! This arrangement did provide power to the decoder, but there were frequent dropouts as I rolled the tender along the track. I hoped that these additional electrical pickups, along with the factory installed pickups on the locomotive wheels, would increase the reliability of operation.

After wiring the tender trucks, I purchased a Bachmann caboose that had electrical pickups to power an interior light. I intended to remove the pickup system from the caboose and use it to replace the Kadee contacts on my tender. When I looked at how the caboose pickups were done, they were so similar to what I had installed on the tender that I left my tender pickups as they were. If I had had the caboose trucks initially, I would have definitely modified their electrical pickup for installation on the tender trucks.