Dead-Rail Conversion of a Max Gray D&RGW L-131, 2-8-8-2, 2-Rail


I received this beautiful 2-Rail Max Gray D&RGW L-131 from a private seller. As an older O Scale model, it required updating for DCC-controlled lighting, motor, sound, smoke, and dead-rail operation (battery power, radio control).

This post is brief because many of the modifications are similar to those from past posts. The most significant modification was removing the open-frame motor with a more “modern” Pittman motor. DCC decoders struggle to control old, open-frame motors. Also, these older motors do not have the strong rare-earth magnets that improve efficiency – an essential consideration for battery power.

LokSound 5 XL Sound Project Settings

I selected a LokSound 5 XL because it provided plenty of power (5A) for a large locomotive. I chose #3608 based on photos of the L-131 I could find online. A heavily-modified LokSound UP “Challenger” Sound Project was selected because of its passing similarity to the L-131.

LokSound 5 XL Pin-out. Note the jumpers to split the heater current and provide dual fan control.
LokSound 5 XL Sound Project Settings #1
LokSound 5 XL Sound Project Settings #2
LokSound 5 XL Sound Project Settings #3. Note that AUX 5 & 6 are used to split the return current from the smoke unit heater.
LokSound 5 XL Sound Project Settings #4. AUX 7 sets steady-state fan output at rest and moving.
LokSound 5XL Sound Project Settings #5. AUX8 controls the synchronized fan output.
LokSound 5 XL Sound Project Settings #6.
LokSound 5 XL Sound Project Settings #7.
LokSound 5 XL Sound Project Settings #8.
LokSound 5 XL Sound Project Settings #9. Note the dual dynamo volume reduction.

Loco and Tender Modifications

The original “open frame” was both inefficient and difficult to control by the DCC decoder, so it was replaced with a more “modern” Pittman 9433L187, 15.1 V motor used in many O Scale locomotives.

The LokSound 5 XL was mounted in the locomotive to reduce wiring between the locomotive and tender. LEDs were used for the marker light, front light, cabin light, and firebox simulation.

The hose required slight displacement to remove the chassis from the boiler frame.

The boiler face plate was removed to allow smoke unit installation and access.

Spring-mounted fan-driven smoke unit. The DCC decoder controls heating and coordinated chuffs.
The numerous locomotive modifications include a new motor, decoder, LED lighting, and smoke unit.

The tender modifications include adding a speaker (with exit holes drilled through the chassis), battery, LED tail and marker lights, and ProMini Air transmitter and Cytron amplifier.

The tender modifications include LED lighting, speaker, battery, ProMini Air receiver, and Cytron amplifier.
Tender modifications showing power switch and battery charging plug
Tender modifications for the small whip antenna. A tiny #56 hole provides the antenna exit.
The “proof in the pudding” video. A smartphone throttle app (Locontrol) communicates with a WiFi-equipped EX-CommandStation integrated with a ProMini Air transmitter that sends wireless DCC commands to a ProMini Air receiver and amplifier located in the tender. The amplifier, in turn, sends track-level DCC to the locomotive’s LokSound 5 XL DCC decoder that controls sound, smoke, lighting, and locomotive motion.

Author: Darrell Lamm

I earned my Doctorate in Physics from the Georgia Institute of Technology in 1982, and before retiring in 2019 I worked for 37 years at the Georgia Tech Research Institute. My last position was Chief Scientist of the Electro-Optical Systems Laboratory. Like many people, my love for model railroading began at an early age, and I rekindled that interest starting in 2017.

2 thoughts on “Dead-Rail Conversion of a Max Gray D&RGW L-131, 2-8-8-2, 2-Rail”

  1. That is a wonderful job and beautiful locomotive. What do you think of the upcoming Blunami product about to come out in a high current version?

    1. Hi Larry,
      Thanks for visiting and enjoying my work!

      The following is just my opinion; others will certainly not agree with me: I’m not a fan of proprietary transmitter/receiver solutions, especially those that lock you into one vendor’s decoders, e.g., Soundtraxx’s Blunami. The good thing about ProMini Air, Airwire, Tam Valley Depot DRS1, Gwire, and Stanton Cab is that you can integrate the receiver with any DCC decoder. I mostly use LokSound and Zimo decoders because they have many locomotive-specific sound projects and handle smoke units well. The Zimo sound file for the Allegheny is astounding. Others may not care one bit about these things.

      My modular approach for the ProMini Air allows you to use a 13A Cytron amplifier, and if you need more, I have integrated Pololu PWM amplifiers with even larger output. All integrated receiver/amplifier solutions involve size or output compromise, and the modular approach allows you to locate the amplifier from the receiver separately.

      Again, just my opinion. Thanks for your time.

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