Railways act as if urban real estate was free. They have such a vast acreage of property and yet they are always moaning about having no resources to enable the trains to run on time.
Today’s invention is an attempt to free up some of that valuable urban land that they now use for washing trains -to very limited effect.
Instead of having centralised train washing facilities, imagine that on many trains there is a washing car. It needn’t be a whole car of course, more a railway trailer. This would be equipped with tanks and water jets. Whenever the train pulling this trailer passed another train, it would automatically activate the washers and spray clean one side of the oncoming vehicle. No need to attempt to spray both sides, since the two machines are bound to encounter each other again soon and clean the other side then.
There would only be a limited need for high pressure delivery, since, by angling the jets appropriately, it would be possible to make use of the oncoming train’s speed to achieve a much greater cleaning effect. Ideally, it would be possible to reuse collected rainwater and thus minimise the need to cart around tonnes of liquid.