2. British Rail Class 373

In 1994, the Channel Tunnel had opened, connecting England and France across the English Channel.  The Eurostar is the main transportation that people used to cross the English channel, with over 9 million people using it each year.  The British Rail Class 373, which operated the Eurostar, can carry passengers up to 300km/h.  However, trains can only put into speed for only 160km/h in the Channel Tunnel.

Why do you think the trains need to decrease its speed when it crosses the channel?