alert
background
barrier
caution
chime
closed
cross
crossing
crossings
danger
flash
flashing
gate
industry
isolated
journey
light
line
locomotive
outdoor
outside
pole
protection
rail
railroad
railway
red
road
rural
safe
safety
sign
signal
signpost
sky
speed
steel
stop
street
symbol
track
traffic
train
transport
transportation
travel
warn
warning
way
white