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Special sneak preview: Iowa Scaled Engineering ProtoThrottle

Read this review from the July 2018 Model Railroader
Iowa Scaled Engineering ProtoThrottle
Iowa Scaled Engineering ProtoThrottle
Recently I tested a pre-production sample of the Iowa Scaled Engineering ProtoThrottle. This wireless Digital Command Control cab is designed to mimic a diesel-electric locomotive control stand in looks and operation. In both cases, the ProtoThrottle delivers.

The receiver. The ProtoThrottle isn’t a standalone DCC system and doesn’t program decoders. The unit also requires a receiver (sold separately) to operate.

One receiver is designed for DCC systems that use WiFi control. These include a Digitrax system connected to an LNWI LocoNet WiFi module, an ESU CabControl system, or DCC systems that use Java Model Railroad Interface (JMRI)-based WiFi control.

The other version has interfaces for an NCE cab bus and a Lenz or Digikeijs ( DR5000 through an XpressNet bus. This is the receiver that I used with an NCE system.

An instruction sheet shows how the DIP switches on the receiver board should be set for each system. I appreciated all the light-emitting diodes (LEDs) on the board (as well as the throttle) that let me know when things were working properly. Once the switches were set, I simply plugged the receiver into an open cab bus plug port using a short length of RJ12 cable.

Controls. The ProtoThrottle measures 3" x 3.2" x 7.6" and weighs 14 ounces. A strap on the back of the case kept the hefty throttle in my hand. There’s also a lanyard hole on the front of the case.

After removing four screws, I could lift off the case and install two AA batteries.

The controls include an 8-detent throttle, a reverser handle with center position, and a brake handle with optional emergency brake functionality. There’s also a spring-loaded horn handle and a bell on/off button. Two knobs control the front and rear lighting functions, including ditch lights and dimmers.

Pressing any key turns the unit on. if left undisturbed, the throttle goes to “sleep” after a time duration that can be set by the user.

An easy-to-read backlit liquid-crystal display (LCD) screen shows the locomotive number, battery indicator, and whether the reverser or emergency brake is engaged. It can also show the fast-clock time when linked to an ISE wireless fast clock or NCE cab bus.

The four buttons around the screen are used to maneuver through easy-to-use configuration menus. These buttons, as well as an auxiliary button in the upper left corner, can also be programmed to trigger decoder functions.

Operation. To work with the ProtoThrottle, a locomotive decoder should be programmed for prototypical operation, including a lot of acceleration and deceleration momentum and manual, non-directional headlight control with a separate dimmer function. The ProtoThrottle doesn’t have decoder programming capability, so a DCC master throttle or programming software such as DecoderPro is required for this step.

The ProtoThrottle brake lever can be set for on/off or variable control. For the latter to work, the decoder must support function-controlled braking and be programmed accordingly.
With the decoder programmed,

With the decoder programmed, I assigned functions to the throttle controls using the ProtoThrottle's Configure Functions menu. The controls can be fine-tuned, including the throttle and braking response. Then I saved the locomotive information in the Load Configuration menu, which acts like a recall stack in a conventional DCC throttle. For more information, download a free copy of the user manual at

I used the ProtoThrottle to run HO and N scale diesels equipped with non-sound and sound decoders, including products from NCE, Model Rectifier Corp., ESU, SoundTraxx, and Train Control Systems. For the Tsunami2 decoder, I programmed the auxiliary button to toggle between independent and train brakes. For the LokSound decoder, I used this button for the drive/hold feature.

I ran various trains on the MR staff layout, the Milwaukee, Racine & Troy, including switch jobs and trains led by multiple-unit diesels. There’s a learning curve, as operations must be done in a specific sequence, just like with a real diesel. For example, the throttle wouldn’t respond until I’d set the reverser.

The ProtoThrottle represents an exciting new direction in train control. I found the experience more akin to a locomotive simulator than simply running model trains on a layout.
Price: $482 (throttle), $99 (receiver)
Iowa Scaled Engineering
22750 County Road 37
Elbert, CO 80106
Wireless operation
Works with any DCC decoder
Requires two AA batteries (alkaline or rechargeable NiMH)

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Plan and design an around the room track plan.

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