alert
barrier
blur
cargo
carriage
caution
cross
crossing
danger
fast
freight
industry
infrastructure
intersection
journey
junction
level
light
line
locomotive
motion
moving
passing
rail
railroad
railway
rapid
red
road
safety
semaphore
sign
signal
signpost
speed
stop
symbol
track
traffic
train
transit
travel
trip
vehicle
velocity
wagon
waiting
warning