You don’t really think that driving the subway would be terribly difficult until you get onto a car with a really bad driver. Usually it amounts to going to fast, stopping too suddenly, starting too suddenly and the like. When they’re going really fast you feel those curves, and you start getting thrown around even when sitting down. A few times in recent memory I had some of these drivers. In one case the train really had a severe jolt when it first started moving. You didn’t want to be without some sort of support on that train.