The 458 is mocked as a failure, but when you looked at the technology of when it was designed and who it was designed by, taking into account they're previous attempts, or lack of. Alot of fitters find the 458 and 460 a good intermediate transition between the old slam door 400 series and the Desiros
Well they are hardly a success story.
Apart from the recent saga with the passenger information screens and in 2000 when all Juniper type units were taken out of traffic by Railtrack due to the runaway 334, the JOP's have been plagued with problems.
For what seemed like months there were only two JOP's in passenger traffic because Alstom were trying to fix the backlog of faults with the aircon, the computer system, the couplers and the corridor connections. Plus they can only work in multiple with other JOP's which makes them inflexable when you compare to other Southern Region stocks over the years.
Even when JOP's were in traffic fully on lines like Alton, they always seemed to get very short diagrams such as two round trips to Alton then ECS to Wimbledon Park and even when they were working on Readings they rarely strayed and 455's and slam door stock were regularly at work vice JOP's.
I thought that they were going to try to get JOP's and Desiro's to work in multiple but it seems as if South West Trains had given up the idea or maybe it was because Siemens and Alstom wouldn't/couldn't find a way to do it.
Certainly is a crime to let 6 year old units rot away, using them on a few Reading diagrams here and there to fill in whilst the last Desiro's are delivered especially seeing as South West Trains had started to grips with them and the mpc figures had finally started improving.
Makes me wonder what would have happened if the same attitude had been taken with Networkers as they have never really fulfilled the expectations that Chris Green and Network Southeast had when they were replacing the EPB's and the 465/9's have not helped seeing as they had to keep VEP's running for a lot longer to cover the poor reliabilty of the refurbished units and even today the diagrams keep getting switched to get Electrostars on the longer journeys leaving the 465/9's to work journeys where they seem to work more efficiently like Ashford and Faversham.
I think that Slash is right about 442's in that South West Trains appear to have an ongoing evaluation program with new parts and specs with the units and that can only be good for future development with other stocks.