Method and apparatus for controlling train positioners using motor energy to determine the mass of the train and the mass of the train to determine maximum deceleration

A method of controlling the operation of a train positioner moving at least one railroad car of a unit train, said method comprising the steps of:

• a. engaging the positioner with the train while the positioner is stopped at an initial location;
• b. moving the positioner and accelerating the train to a constant speed;
• c. measuring the constant speed of said train as reached in step (b) above;
• d. determining the energy needed to accelerate the train to the constant speed;
• e. determining, from the constant speed measured in step (c) and the energy determined in step (d), the apparent mass of the train moved by the positioner;
• f. calculating, from the apparent train mass determined in step (e) and a maximum force to which the positioner should be subjected, a deceleration point and a deceleration rate for the positioner adequate to stop the train by a predetermined final location;
• g. decelerating the positioner beginning at the deceleration point and at the deceleration rate calculated in step (f) above;
• h. after the train has completely stopped, disengaging the positioner from the train and moving the positioner to the initial location;
• and
• i. repeating steps (a)-(h) above for each index cycle of the positioner.

Apparatus for controlling the operation of a train positioner moving at least one railroad car of a unit train comprising:

• a. means for engaging the positioner with the train while the positioner is stopped at an initial location;
• b. means for moving the positioner and accelerating the train to a constant speed;
• c. energy means for determining the energy expended by the positioner in accelerating the train to the constant speed and for calculating therefrom the apparent mass of the train;
• d. means for calculating, from (i) the apparent mass of the train, (ii) a maximum force to which the positioner should be subjected, and (iii) a deceleration rate, a deceleration point adequate to stop the train by a predetermined final location;
• and
• e. means for initiating deceleration of the positioner at the deceleration point and decelerating the train at the deceleration rate until the train is stopped by the final location.