Re: Slip Coaches: Back When British Express Trains Detached Passenger Cars at Speed
Author: Ed Workman
Date: 07-09-2018 - 13:37
R Z wrote
When GW showed his success, Brits were quick to point out he didn't invent the air brake, and claimed credit for themselves.
ONe of the trade press editors wrote some like ' Any farmer, in a few winter nights can invent an air brake, but making it work ....]
Inventing something and proving it successful are two different things.
And when Smith showed his vac brak in competition, Brits lamented that there was no British brake. ONe writer went so far as to say Smith claimed not to be American but was a brit expat
Creamer, a US inventor of a 'wind-up" brake went to Britain to show his device [185x] and spoke before engineers. In that speech he enumerated all the brake inventions he could find, and the list was extensive, albeit very few if any are now recognizable.
Brits claimed the vac was soooo simple and the triple sooo complicated.
GW replied that the triple was not really complicated, but it was complicated to explain in words.
Making the vac practical added complication such as double ejectors valves to make it Automatic, that is part failure would set the brakes.
And as you say the size of the parts on a car had to have an area much larger than an air brake-12 or so psi v 50 or so. With size came weight such that vac parts were heavier than WAB parts
Brits invented unit trains [merry-go-round trains], but with 26 ton 4 wheel wagons, a jump to be sure from 10-15-20, but..
The best of the 4 wheel wagons were not scrapped and got piped or braked. With brakes, freight train speed was increased to be 'competitive'. Short wheelbase wagons derailed, and the permitted minimum wheelbase was incrementally increased until derailing was no longer a special concern.
Many decades ago a Brit trying to hammer nails into the WAB coffin compared steam consumption of a WAB pump to the ejector. An air pump only must pump until the main reservoir [as you are well aware- this is for the others] reaches the pressure set by the governor and stops until the pressure drops a notch lower, but the ejectors must be continuously shooting steam into the atmosphere. Great Western added axle vac pumps to its carriages, but those 'didn't count' toward more complication.
Thanks for your discussion.