Railroad communication system

• US 5,039,038 A
• Filed: 10/03/1989
• Issued: 08/13/1991
• Est. Priority Date: 09/14/1983
• Status: Expired due to Term

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Nichols, Richard E., Dahlman, Dennis B., Scharla-Nielsen, Hans, Delaruelle, Dale H.
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US07/416,516
• Time in Patent Office: 679 Days
• Field of Search: 246/3-5, 246/187 C, 246/187 B, 246/187 A, 246/187 R, 246/182 R, 246/182 A, 246/182 C, 246/182 AA, 246/182 AB, 246/167 R, 246/167 A , 246/167 D, 246/28 R, 246/28 D, 246/34 R, 246/133, 246/134, 340/825.5, 340/48, 303/20, 303/15, 303/3, 105/61
• US Class Current: 246/3
• CPC Class Codes: B60L 15/32 Control or regulation of multiple-unit electrically-propelled vehicles
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60T 13/665 the systems being specially adapted for transferring two or more command signals, e.g. railway systems B60T13/662 takes precedence
• CPC Class Codes: B61L 15/0027 Radio-based, e.g. using GSM-R
• CPC Class Codes: B61L 27/20 Trackside control of safe travel of vehicle or train, e.g. braking curve calculation
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

A radio communication control system for a lead unit and a plurality of remote units is disclosed. The system has a protocol for establishing a communication link between the lead unit and the one or more remote units in the system which prevents any of the units in that system from processing messages or commands from other units in other train systems or processing messages or commands originating from units within a train system which are addressed to other units within the system. The communication system also includes a communications channel contention system for minimizing the probability of multiple units transmitting on the common communication channel at the same time and for insuring that the highest priority communications in each train are transmitted first in time measured from the end of the latest transmission on the radio communications channel. The invention also includes apparatus for verifying the establishment of the communications link by means of signaling through the mechanical coupling in the train and monitoring the radio response. The invention further includes an improved flow rate sensor for use in a remote unit for determining when significant air flows occur into the brake pipe of the remote unit. The invention further includes an air pressure regulation system which prevents the fluctuation of the air pressure in the equalizing reservoir of the lead and remote units consequent from either leakage or change in the ambient temperature.

Claims

1. In a communication system for use with the control of a railroad train having a plurality of transceivers, the transceivers being located on lead and remote units of the train, a lead unit controlling the operation of a remote unit by way of a transmission which includes a command transmitted by a lead transceiver over a communication channel therebetween, a remote unit transmitting a reply to a command confirming execution of the command, and information representative of the operation of a remote unit, a system for controlling which unit transmits on the channel comprising:

at each respective unit,

first means, associated with the transceiver of that unit, for detecting the ending of the latest transmission by any transceiver on the communication channel; and

second means, coupled to said first means, for causing its associated transceiver to initiate a transmission upon the termination of the delay of a prescribed period of time after the detection of the ending of said latest transmission by said first means, and wherein

each transmission over said communication channel is prioritized into one of a plurality of different ranges of time delay that must terminate before that transmission may be initiated, such that a higher priority transmission is initiated after a time delay that is shorter than any time delay within a range of time delays of a lower priority transmission.

2. A system according to claim 1, wherein, within a respective range of time delays into which a transmission is prioritized, the time delay that must expire before a transmission is initiated is randomly selected.

3. A system according to claim 2, further comprising:

a second repeater at a location other than on the train for receiving transmissions from a lead or remote unit and retransmitting such transmissions, said second repeater having a transceiver the initiation of transmission from which is prioritized into a range of time delay that follows the range of time delay into which retransmission of a message by the first repeater is prioritized.

4. A system according to claim 1, wherein a remote unit functions as a repeater for receiving a transmitted message from a lead unit and retransmitting that message, and wherein the time delay that must expire before the remote unit retransmits the message is the same as that for transmitting a reply to a transmission from the lead unit.