Puzzle #02: Getting past the freight train

Try this week’s challenge – to keep the railways running smoothly, set by Matt Scroggs. And test your science knowledge with our quick quiz

8 May 2019

#02 Getting past the freight train

New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.

A very long passenger train is heading along a single track railway behind a freight train composed of a locomotive and three freight trucks. They are approaching a station where the freight train is due to unload. To keep to its timetable, the passenger train needs to leave before the freight train will have had time to unload.

At the station, there is a siding that either train could drive into. The siding is large enough to hold a locomotive and one freight truck, or two freight trucks. Both trains have couplings at the…