High Speed Train Tilt Control

Acela High Speed Train

The sole purpose of train tilt control is passenger comfort.

In the United States, high-speed trains must share the same tracks as all other rail services. Since the tracks were not initially designed for high speeds, especially in turns, the passenger cars of these trains are tilted while turning to alleviate the effects of centrifugal forces. A tilt sensor is required that can provide highly accurate data on the vehicle dynamics to a computer that determines the degree of corrective tilt required to assure a smooth ride.

Watson Industries responded to this need by developing and producing the Train Measurement System (TMS-E232). The TMS provides superelevation (roll angle), roll rate, yaw rate and lateral acceleration output data.

Watson Experience

Watson Industries initially brought the TMS to market in 1993. In 1997 Watson began large-scale production to supply Amtrak’s Acela high speed train.

Applicable Products

Technical Challenges

One of the most difficult problems with this application is the required mounting location of the tilt sensor. To provide accurate track data, the sensor must be mounted directly to the suspension bogie. Many solid-state gyros manufactured today are too shock and vibration sensitive for the bogie’s 4 G vibration environment. However, the gyro sensors that are used by Watson are rugged and will output accurate data in this environment for extended periods of time.

Furthermore, a gyro mounted on the outside of a train cab must be enclosed in a rugged case to protect it from weather, debris, pressure washing and EMI/RFI. The Watson TMS is enclosed in a sealed, durable steel housing with internal vibration mounts and electrical isolation.


  • High shock: 200 G
  • Vibration: 4 Gs rms operational from 9 to 100 Hz
  • Electrical isolation: 4 KVolts
  • Submersible: NEMA Type 6 standards for submersion, corrosion and water spray due to pressure washing requirements.
  • EMI/RFI protection: An electric locomotive has thousands of Amperes of current switching locally. Protection to 20 Volts per meter is required.
  • Velocity Input: Our sensors in this application require a velocity input from an outside source. There are three options for this input: An analog voltage, digital RS-232 signal, or pulses from an encoder wheel.

Typical Options

We are able to accommodate your custom needs. Go to our custom product modifications page for a listing of the most common custom options we support.

Custom options for this application:

  • Non-standard mounting orientation