Oscilliograph Car --- The main equipment in this car is an accelerometer, which consists essentially of a mass attached to one end of thin flexible plate, the other end of the plate being fixed firmly to the casing of the accelerometer. The space within the accelerometer casing is filled with a damping fluid (usually silicon liquid). The cantilever plate is strain gauged so that the deflection of the mass 'm' is sensed. This is calibrated to indicate the acceleration to which the mass is subjected. This acceleration is recorded in the form of an accelerogram. Thus the vertical and lateral acceleration on any part of the vehicle where the accelerometer is installed can be recorded. In track monitoring runs the accelerations at the loco cab floor are recorded by keeping the accelerometer as close to bogie pivot as possible.

These cars are used to monitor high speed routes where the sectional speed exceeds 100 km/h on BG. These cars are run once in six months to assess the riding quality of the track as distinct from actual track geometry recorded by the Track Recording Cars. Recording is done at the maximum sanctioned speed of the section. On Rajdhani routes recording is done once in 4 months. Type - BLRZ.