Hi there, I’m examining the railroad cars.
In Japan, vehicles drive on the left side of the road.
This railroad car is a women-only carriage.
A car with more cars on both sides is a car that hooks into other cars... specifically other railroad cars. They have hooks on both sides, they hook into other cars, and they fit all the requirements of this vocab word's kanji.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.