Exercise 3: sample answer

Technology: the railway and the telegraph made it possible to travel quickly and to send a time signal along the line, so a single time could be both needed and supplied.

Safety: trains running on one line to clocks that disagreed risked collisions and mistakes, so a common time reduced danger.

Money: confusion over timetables meant missed connections, disputes between companies and lost custom, so a single time was cheaper to run.

Was a law necessary? A reasonable view is that the railways and the public had already largely agreed, so the 1880 law mostly confirmed what was in practice, but it settled disputes in courts and for legal documents, where the meaning of a time could affect a contract or a deadline (check the circumstances). Either position is acceptable if you give a reason.