We’re used to staring out of bright tube trains into dark tunnels, but once, the tunnels were whitewashed in brilliant white paint. This was thanks to the fact that both people were still wary of travelling in dark tunnels, but also as tube train lighting was itself not as bright as we use today.
Painting the tunnels in white paint would help to make the journey seem less oppressive, and from the railway’s perspective, using whitewash would help diffuse the in-tunnel lighting more widely making overnight maintenance works easier.
The idea of covering the inside of the tunnels with whitewash was thanks to the Central line’s chief engineer, Mr E P Grove.
To this end, he took inspiration from an apparatus for washing hops, used in making beer. A spray apparatus used by the hop washers was thought to be suitable for conversion for use on the London Underground.
Beer truly does solve everything!
This hop machine is on account of the misty spray which it throws over and under a bush, called the “mistifier,” and its application to the Central line no doubt mystified the travellers one morning when they found themselves riding through enclosing walls of snowy whiteness.
The modified hop washer was fitted to the back of a train carriage, and when in action, was described as being like a huge Catherine Wheel on the back of the train.
Inside the carriage, which was one of the Central line’s early experimental multiple-unit cars, a tank was fixed holding about 1,200 gallons of whitewash, and this was connected to the small tank containing the pump.
A special cover prevented the whitewash from covering the third rail, which carries the electricity needed for the trains.
Due to dirt build-up, the special train would run through the tunnels every night, spraying a whitewash onto about 2 miles worth of tunnel linings per night. It would make two trips, one loaded with plain water to wash the walls, then then on the second trip, it would spray around 850 gallons of whitewash onto the tunnel walls, on a journey lasting around 45 minutes.
The Railway and Locomotive Engineering magazine wrote the the morning’s commuters are “sure of bright, clean surroundings and plenty of light as they are carried along to and from business in London’s deep tube ‘white way.'”
Popular Mechanics, June 1906
The Street Railway Journal, 21st July 1906
Literary Digest, August 1906