The first escalators in widespread use were in Paris and London. But I think the real reason is cost: a metro system will pay for the extra capacity of a wide

The first escalators in widespread use were in Paris and London. But I think the real reason is cost: a metro system will pay for the extra capacity of a wide escalator. A shopping centre would prefer people not to hurry, can use the space for displaying goods, and thus chooses an escalator sized for one person.