单选题 RailTraq is not responsible ( ) delays to departure or arrival times.

单选题 These bar couplers are preferable ( ) semi-permanent coupling.

单选题 The way cab signaling is used depends ( ) whether the system is intermittent or continuous.

单选题 It consisted mainly （ ） decisions made by local signal operators or members of the train crew.

单选题 We’ve come a long way ( ) the link and pin coupling of old.

单选题 The use of satellite information, microwaves, and data links are adding ( ) new train management systems.

单选题 Fees may apply ( ) the case of cancellation.

单选题 A stop is a designated point on a rail line for passengers to ( ) and exit a train.