Power selection system for a consist of locomotives

Apparatus for controlling the number of on-line locomotives of a consist thereof having a lead locomotive and a plurality of trailing locomotives, where each locomotive has a predetermined, efficient high throttle position and a desired low throttle position, said apparatus comprising:

• a plurality of control units including a lead unit for said lead locomotive and at least a first trail unit and a second trail unit for controlling the throttles of corresponding first and second trailing locomotives,
• an electrical control line extending from said lead unit to said trail units in serial order,
• said lead unit including operator-activated means for producing either a subtract power command or an add power command to subtract from or add to the number of on-line locomotives of the consist, means for generating a cutout control signal and transmitting the same to said trail units along said control line, and control means for providing said signal with a magnitude that changes in one direction in response to said subtract command and in the opposite direction in response to said add command,
• said control signal generating means having circuitry for providing said signal with an identifier pulse portion that indicates that a received signal at said trail units is a valid control signal,
• each of said trail units having a decoder responsive to the magnitude of said signal for setting the respective locomotive throttle at either the high position to put the locomotive on line or the low position to cut it out, said decoder having means responsive to the absence of said identifier pulse for disabling the decoder to prevent cutout of the locomotive,
• said trail units being provided with means responsive to said signal for changing the magnitude thereof in said one direction by a predetermined amount as said signal is conducted rearwardly in the consist from each trail unit to the next succeeding trail unit, whereby valid control signals cause locomotives to be successively throttled back from the rear of the consist and returned on line from the front.

A method of controlling the number of on-line locomotives of a consist thereof having a lead locomotive and a plurality of trailing locomotives, where each locomotive has a predetermined, efficient high throttle position and a desired low throttle position, and where the trailing locomotives for control purposes are numerically designated in sequence beginning with the first trailing locomotive immediately behind the lead locomotive, said method comprising the steps of:

• generating a cutout control signal in said lead locomotive and transmitting the control signal to the trailing locomotives in serial order;
• providing said control signal with a characteristic that progressively changes in response to a substract power command or an add power command;
• decoding said control signal at each trailing locomotive and setting the throttle thereof at either the high position to put the locomotive on line or the low position to cut it out;
• modifying said characteristic of the control signal as it is transmitted from the first trailing locomotive to successive trailing locomotives, in a manner such that locomotives are successively throttled back from the rear of the consist and returned on line from the front;
• periodically transmitting a status report from said trailing locomotives to said lead locomotive that indicates the on-line or off-line status of the corresponding locomotive;
• and
• ceasing execution of said subtract or add power command when the status report indicates that a trailing locomotive has been cut out or put on line, whereby one trailing locomotive at a time is either cut out or put on line in response to the subtract of add power command.

Apparatus for controlling the number of on-line locomotives of a consist thereof having a lead locomotive and a plurality of trailing locomotives, where each locomotive has a predetermined, efficient high throttle position and a desired low throttle position, said apparatus comprising:

• a plurality of control units for respective lead and trailing locomotives for controlling the throttles of the trailing locomotives,
• each of said units having operator-activated means for producing either a subtract power command or an add power command to subtract from or add to the number of on-line locomotives of the consist, and means for generating a cutout control signal having a characteristic that changes in response to said subtract and add commands,
• each of said units further having a pair of lines interconnected at a junction point and adapted for connection to corresponding trainline wires extending from said lines to the short and long hood trainline connectors respectively of the locomotive, an output lead connecting said control signal generating means with said junction point for transmitting said control signal thereto, and a decoder connected with said junction point and responsive to said control signal characteristic for setting the respective locomotive throttle at either the high position to put the locomotive on line or the low position to cut it out,
• each unit having means for rendering said control signal generating means operable when the unit is in the lead locomotive, whereby such lead unit is capable of generating said control signal and transmitting the same to the junction point therein for transmission to units in trailing locomotives, and means isolating said output lead from said junction point to prevent control signal conduction along said output lead away from said junction point,
• each unit being provided with means for disabling the decoder thereof when the unit is in the lead locomotive, whereby locomotives equipped with said control units may be employed as lead or trailing locomotives and the control units will respond without being especially set up for a lead unit or trailing unit function.

Apparatus for indicating the number of on-line locomotives of a consist thereof having a lead locomotive and a plurality of trailing locomotives, said apparatus comprising:

• a plurality of units including a lead unit for said lead locomotive and a trail unit for each of said trailing locomotives,
• an electrical control line extending from said lead unit to said trail units in serial order,
• said lead unit including interrogation means for periodically transmitting an interrogation signal to said trail units along said control line, said interrogation signal having a voltage that increases over a predetermined time duration,
• said trail units including voltage-responsive means in each unit responsive to each interrogation signal for causing it to drop in voltage by a predetermined amount as said signal is conducted rearwardly in the consist from each trail unit to the next succeeding trail unit,
• each of said trail units having means for sensing the on-line or off-line status of the corresponding locomotive, and reporting means receiving each signal from said voltage-responsive means of the unit and responsive to a predetermined voltage level thereof for causing a pulse to appear on said control line when the corresponding locomotive is on-line, whereby pulses from said reporting means in the trail units are time spaced,
• said lead unit further including means responsive to said time spaced pulses for indicating the number of locomotives on line.