It’s emerged that hybrid battery-powered alternatives are being considered for the electrification of the Valley Lines rail services – which run to Penarth.
New IPEMU trains [Independently Powered Electric Multiple Units] – which are powered by lithium iron magnesium phosphate battery technology – are being considered as an alternative to conventional electric units – and could reduce the huge cost of completely electrifying the Valley Line services – currently run by Arriva Trains.
One of the problems with electrifying services to Penarth is the lack of headroom on some bridges – particularly the Stanwell Road bridge which only has a few inches of clearance for the current ageing fleet of diesel trains.
Installing electrification would involve the extremely costly closure and re-build of the Stanwell Road Bridge or somehow reducing the track level to increase clearance underneath the bridge. Other options are to use train units which have various forms of intermittent on-board independent power.
The IPEMU trains can run on electrified and non electrified lines and – like some cars – have hybrid propulsion systems in which the traction batteries are automatically re-charged every time the brakes are applied. The units can also plug-in for charging from the mains whilst they are waiting at stations.
The units are being designed to “fill gaps” in the rail network where full electrification hasn’t – or can’t be – economically installed .