Axle generator, to install on the axle of a locomotive, measures speed and wheel slip conditions for better tractive effort

TMV Axle Generators, manufactured in-house with stringent tolerances,
precisely generate signals to serve as a reliable reference in capturing true wheel speed.

In addition to their high degree of accuracy in matching axle rotation, TMV Axle Generators are meticulously constructed with superior materials for durability—all within a compact profile at an affordable price.  

The result: customers can count on correct wheel speed that can be conveyed to the control system,
so that proper adjustments can be made to minimize wheel-slip and maximize adhesion.

Active Axle Generator:

The Active Axle Generator (pictured above) is a Powered Axle Generator, and operates on a 10-20 VDC supply from an isolated source—typically provided by the TMV TECU, at 12VDC.   A single cable, carrying power and the output speed signal, connects to the locomotive electronics via a Military Specified (MILSPEC) type connector. Because of these strong components and the slim profile, successful reliability is achieved, even through harsh conditions such as cold, ice, snow and debris.

Types of Active Axle Generators Available:

  • 120 ppr
  • 60 ppr

Magnetic Axle Gen

Black TMV axle gen Magnetic Passive 2 wire sophisticated design
TMV’s Magnetic Axle Gen
top view of TMV magnetic axle gen to show its ultra slim profile low profile design
TMV Magnetic Axle Gen has an Ultra-Slim profile

TMV offers a direct replacement to 2-wire, Passive axle generators. These magnetic axle generators reliably measure wheel rotation and wheel speed at 20ppr (20 pole) and 60ppr (60 pole) output designations.

Older locomotives, such as pre-1990’s locomotives, often require this 2-wire magnetic axle alternator to communicate with their onboard computers, control systems, speedometers, speed recorders, event recorders, and other devices that require speed data.

The new TMV magnetic axle gen is a simple but sophisticated device designed for easy install and all things familiar. Oil-free, with a standard driveshaft and easy access to bolts for install, this is the straightforward and clear choice for those wishing to save time and money.

Ordering Axle Generators

TMV offers four types of Axle Generators

As mentioned above, TMV’s Axle Generators were designed for DC traction locomotives. They develop speed signals from the rotation of the drive shaft, which are sent through Axle Generator Cables. These are routed to your locomotive electronics, to recording devices such as control system, event recorder, speedometers, etc. TMV offers Axle Generator kits, which contain all the parts needed—including cabling—to equip your DC traction locomotive with the speed information you depend on. After all, without speed sensing, your control system can’t monitor and maintain wheel-to-rail adhesion or traction! This is the most important sensor of the TECU Control System.

Part Numbers:

T-06100/00 – Active Axle Generator 120ppr
T-17102/01 – Active Axle Generator 60ppr
T-18102/02 – Magnetic Axle Generator 60ppr
T-18102/03 – Magnetic Axle Generator 20ppr

Note: These part numbers are for the axle generators alone, for Axle Generator Kits, please call TMV at 519-624-8219 or email

Examples of Axle Generator kits from TMV

WheelSlip Testing Video—Notice how the TMV wheel gains speed more evenly and progressively, resulting in a higher speed sooner with less slip.

Axle Gens on Locomotives

Technical Information and Photos:

TMV manufactures 60 pulse (PPR) Part # T-17102/01 and 120 pulse (PPR) Part # T-06102/00 active axle generators which can serve as direct replacements to other brands of axle generators.

Installed Axle Generator from TMV, brand new and shiny to modernize for better control and calculated adhesion
Installed Axle Generator

Click here to see Knoxville Locomotive Works website page Locomotives that Emit Less, Consume Less, and Do More

speed probe wire suited for speed probe port on traction motor for speed evaluation this one has three wires and no delicate resistor more robust
TMV Speed Probe

If your locomotive has DC traction motors fitted with speed probe ports,
or if you prefer the no-profile safety of a speed probe, click here.