trac - trai
- trace
- tracer
- track
- track adhesion
- track alignment
- track anchoring
- track and station improvement
- track arrangement
- track battery
- track battery lead
- track bed
- track block
- track block section
- track block signaling
- track block signalling
- track bolt
- track bond
- track box
- track broom
- track cant angle
- track capacity
- track capacity increase
- track center
- track centerline
- track centres
- track change
- track changes
- track chargeman
- track chart indicator
- track choke
- track circuit
- track circuit arrangement
- track circuit control
- track circuit controlled equipment
- track circuit controlled locking
- track circuit current frequency
- track circuit equipment
- track circuit layout
- track circuit leakage
- track circuit length
