(From the publisher):
Professor Childermass has made an astonishing discovery. Behind a bricked-up wall in his house is a rickety old trolley...and it can travel through time! Soon Johnny Dixon, his friend Fergie, an the professor are headed for Constantinople, 1453 - and grave danger. The professor has a desperate plan to alter history, but it may cost him his life. Can Johnny and Fergie stop the professor before it's too late?
Original title: The Trolley to Yesterday
Genre: Fiction→ Children & Young Adult→ Fantasy→ Time Travel