alone
archaic
area
banded
bar
barrier
bolt
caution
chain
closed
cogwheel
crank
cross
crossing
danger
down
gate
gearwheel
green
handle
light
mechanism
obsolete
oily
old
open
outdated
paste
railroad
railway
red
remote
risk
road
rural
secretion
sign
signal
signs
sprocket
stop
symbol
toothed
track
tracks
transportation
trees
triangle
warning
white