1)When two trains meet, people lift one of them off the track
When two trains meet, one of them is lifted off the track.
2) Bamboor trains are cheaper than ordinary trains.
Ordinary trains aren't as cheap as Bamboor trains.
3) People carry this train round the other one.
This train is carried round the other one.
4) Bamboor trains are more popular than ordinary trains.
Ordinary trains aren't as popular as Bamboor trains.