It wasn’t until the mid-nineteenth century that underground rail travel was envisaged, deemed to be quieter and less disruptive than overground, not to say obviating the need to demolish properties in more salubrious areas.
Underground rail travel posed a problem for the engineers as passengers rather inconsiderately needed to breathe, and existing coal-fired trains emitted a toxic mixture of steam and sulphurous smoke which had a tendency to suffocate both crew and their passengers.
[T]he world’s first underground railway, opened on 9th January 1863. The line, which still runs alongside Farringdon Road, was built as cheaply as possible so rather than design new locomotives, the company simply adapted existing ones – steam trains.
Trials were undertaken burning coke instead of coal but because of poisonous gases it was thought preferable that tunnels were filled with coal smoke instead, prompting The Times to comment ‘A journey . . . is a form of torture which no person would undergo if he could conveniently help it’. Train drivers were not convinced with the company’s assertion that asthmatics found the smoky atmosphere helped breathing and grew thick beards to try and filter the black soot; they even named their locomotives after tyrants – Mogul, Czar and Kaiser.
Enter Sir John Fowler, Bt. who designed the world’s first experimental fireless locomotive nicknamed “Fowlers Ghost”. Propulsion was achieved by using heated bricks placed in a conventional coal-fired engine to produce steam. It was deemed a failure after only one test run presumably the locomotive’s footplate was just a little too hot for comfort for the engine drivers trying to manhandle red-hot bricks. Fowler would later redeem himself as the genius who designed the Forth Rail Bridge.
It was back to the drawing board this time to design condensing engines which emitted less steam and smoke, the engines emissions were routed into large tanks behind the locomotive, which were then vented off as the train emerged from the tunnel. Because the tunnels were under roads, the venting would spook any horses that happened to be overhead, so doubt prompting the cabbies driving Hansom cabs to complain. This method meant that frequent breaks in the tunnel were needed to let off steam and evidence of which we can still see today.