Just leaving Whitechapel station.
This is an Underground train, but it’s not a Tube train, although some folk will mistakenly call it one. It’s a District Line train, and they (and Circle, Metropolitan, and Hammersmith & City trains) are bigger, and don’t run in tubes drilled deep underground like the tube trains do. These lines run in trenches dug from the surface and bridged over.
You might notice that just here there are five rails to each track: two running rails, with shiny tops, that the wheels roll on; two electric rails, with dull grey tops, that the electric pickups slide along; and one check rail with a rusty top (N.B. the rail with a red top is a shiny running rail reflecting a red train – the check rail is the one next to it). There are check rails just here because it’s a tight curve, and there’s a risk of derailment otherwise; most of the way there aren’t any check rails.
©Clive K Semmens 2006