QUESTIONS

Q : Is it true that American heavy diesel train engines are rarely, if ever, turned off?

Tina Owen, West Bromwich, W. Mids.

Q : Are there any castles in Africa?

H. E. King, Bury, Lancs.

Q : The great wall of the Roman town at Silchester in Hampshire was built of hammer-dressed flint and stone, but there are no rocks nearby. Where did they come from?

R. J. Andrews, Farnborough, Hants.