Abstract: A Node-B sends a polling message to a wireless transmit/receive unit (WTRU). The WTRU sends an uplink synchronization burst in response to the polling message without contention. The Node-B estimates an uplink timing shift based on the synchronization burst and sends an uplink timing adjustment command to the WTRU. The WTRU then adjusts uplink timing based on the uplink timing adjustment command. Alternatively, the Node-B may send a scheduling message for uplink synchronization to the WTRU. The WTRU may send a synchronization burst based on the scheduling message. Alternatively, the WTRU may perform contention-based uplink synchronization after receiving a synchronization request from the Node-B. The WTRU may enter an idle state instead of performing a handover to a new cell when the WTRU moves to the new cell. A discontinuous reception (DRX) interval for the WTRU may be set based on activity of the WTRU.

Abstract: A diesel electric locomotive has a dynamic braking system including a plurality of traction motors connected across dynamic braking grids. Air blowers for cooling the grids have motors which are connected across the grids. The failure of any motor is detected by monitoring the voltage across the motor with respect to a reference potential. The reference potential is developed in a bridge arrangement wherein the bridge imbalance is detected by a current sensor or by a reference potential generated in another motor circuit where another current sensor is used to detect a variance from the reference value. A circuit responsive to failure signals but voltage isolated from the traction motor circuits actuates an indicator as well as a relay for diminishing or terminating the dynamic braking function.