18.08.17
New Elizabeth Line trains bugged by insect problem in early testing
The wind screen wipers on TfL’s new Class 345 rolling stock to run on the Elizabeth Line encountered some difficulties in early testing from a build-up of insects, RTM can exclusively reveal.
Despite being tested in a state-of-the-art facility in Austria at the start of this year that ensured the trains could withstand extreme weather, back in London, TfL engineers found that the windscreen wipers were not capable of clearing bugs from the windscreen.
Though the problem was spotted and solved in early testing for the trains, it shows that every small detail is vital when it comes to the design of crucial new rolling stock.
Speaking exclusively to RTM, TfL senior project manager for rolling stock David Sherrin explained about the peculiar problem that the Class 345s encountered early on.
“We took a vehicle over to Vienna and tested the windscreen wipers in Arctic conditions, but one of the problems we had with the first trains down in London was with the windscreen wipers,” he said.
“In the summer, you use the windscreen wipers to clean bugs off the windscreen, and we had tested the wipers in wind, snow, rain and ice, but not with bugs, and we found the trains had great difficulty getting the bugs off the screen.”
Sherrin went on to describe how TfL went about adjusting the design to overcome the issue that had cropped up early on.
“We changed the software of how the windscreen wiper works and the amount of force it uses to sweep across,” he continued.
“When you have a dry windscreen, you need a lot of force to push the blade across, whereas when there’s snow, rain and ice on there, it doesn’t need as much force.”
TfL added that windscreen wipers were often a source of unreliability on new units. Some of this was down to the fact that the Class 345 requires a wiper system which is capable of clearing a large swept area over a complex curved windscreen, so the wiper not only needs to be reliable but also needs to be capable of dealing with a variety debris, including snow, bird strikes and insects.
The company told RTM that manufacturers Bombardier employed an electropneumatic wiper drive on the Class 345, as opposed to an electric motor driven wiper.
This relatively new system brings together the reliability of a conventional pneumatic wiper drive with the functionality of an electronic control unit, which allows the use of prognostics to monitor the performance of the system.
The wiper system was also subjected to durability and functional testing to prove its reliability. When the Class 345s were tested in London they were exposed to flies and other summer debris, and several weeks of trial day-time operations between Liverpool Street and Southend Victoria allowed the performance of the wash wipe system to be optimised for these conditions.
Sherrin also told RTM that the roll-out of the Class 345s was delayed for a month as TfL wanted to ensure passengers and drivers had total confidence in the new rolling stock.
Look out for the full interview with Sherrin in the August/September edition of RTM, hitting desks on 6 September. To receive your copy, you can subscribe by clicking here.
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