3
background
blackish
button
connected
direction
freight
gears
graphic
gray
green
icon
illustration
industry
journey
line
linear
locomotive
mark
metal
metro
motion
pictogram
rail
railroad
railway
red
road
sign
silhouette
speed
station
steel
subway
symbol
tangent
technology
three
track
traffic
train
transit
transport
transportation
travel
vintage
way
wooden