SECTION 4

Complete the notes below. Write ONE WORD ONLY for each answer.

Questions 31-40

Overheating on the London Underground train system.

Complete the notes below. Write ONE WORD ONLY for each answer.

Overheating on the London Underground train system

The reason why the system gets so hot is because some tunnels are very narrow and

Another reason is that the original designers didn't expect the fast

growth.

often block air vents behind seats on train carriages.

There are some primary issues for engineers, so they have to consider how the system would make people on the

feel and how

could be retained if large shafts were made, as well as the impact of the shafts on London's buildings and

There are some solutions. First of all, new large

have lowered temperatures slightly.

Secondly, large amounts of

might help cool the air.

There are some benefits. For example, heat could be used to remove ice from the

When a solution to overheating is found, there could be an increase in