- cross-walk
- crossbar
- crossbond
- crossed cheque
- crosshead engine
- crossing
- crossing gate
- crossing station
- crossing time
- crosswind
- cruise liner
- crutch
- current collector
- Current account
- Current assets
- current rate
- current set
- curve hand
- curve lubrication
- curved crossover
- curved diamond
- crew
- cribbing
- critical engine
- critical wing
- cross brace
- cross grain
- crossing keeper
- crossing watchman
- crossover
- crosswalk
- crosswind landing
- custom house
- customs clearance
- Customs Department
- customs seal
- cut
- cut list
- cut spike
- cutter dredge
- cutter dredger
- cruising altitude
- cruising speed
- CW radar
- cyclic pitch
- cylinder
- cylinder level
- dam structure
- damaged car
- dead astern
- dead crossing
- deadhead
- deceleration lane
- deck pillar
- decked
- deckhead light
- deferred
- damaged wagon
- dancing tie
- Danford anchor
- day range
- dead calm
- dead freight
- deck girder
- decking
- declination angle
- decomposition chamber
- damper
- dancing sleeper
- day traffic
- dead ahead
- debenture
- debit request
- delta wing
- deaerator
- debit note
- deck line
- deflector
- decoding device
- definite term
- deflection
- departure line
- derailing switch
- derailment criterion
- desire line
- detail fracture
- deviation detector
- departure signal
- Deposit account
- derailing point
- design lane
- differential braking
- derailment
- designed frequency
- deviation signal
- diaphasic jet
- differential effect
- dike body
- dike foundation
- dike structure