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Most of Porterbrook’s work to date has focused on the Class 319 Flex, but the concept could be deployed on other fleets. Isbern says the Marshlink route from Ashford, deep in third-rail territory, is an option - it only needs DC plus diesel power.
“The Flex concept could be deployed on fleets such as Electrostar and displace DMUs for use in other parts of the country,” he says.
Simpson says there is no Flex ready yet, but work has begun. And timescales for the project are impressive.
She explains: “When production is up and running, each ‘319’ will take four to six weeks to convert. The rafts will be built in advance and simply be bolted on to the train during conversion at works, thus minimising downtime.
“The design of the control system is largely developed and an Ethernet backbone will be used to monitor output and balance loading between the two engine rafts. The physical modifications needed are relatively straightforward and are largely limited to the driving vehicles - fitting the new engine/alternator raft, some new control technology and some minor relocation of existing equipment. It is a modular concept and it is cost-effective as a result.”
She admits that while the first train will take longer, as per all usual rebuilds and refurbishments, the timescales will improve dramatically when the production is up and running. Initially eight Class 319s will be converted, and form part of the Northern fleet of 32.
“The first four could enter traffic in December 2017,” Isbern tells RAIL.
The ‘319s’ to be converted have been identified by painted number already. Initially they will all be ‘319/4s’, but any of the four sub-classes could be used. Isbern says it makes sense to use the ‘319/4s’ first as they are the most readily available. All of Northern’s Class 319s in traffic currently are ‘319/3s’, but ‘319/4’ Flex units will be able to couple and work in multiple with any ‘319’ sub-fleet.
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Isbern adds: “We don’t know yet which exact routes Northern will use the Flex units on. We know they outperform a ‘150’ on a number of different routes and diagrams, and will certainly outperform a Pacer. We are working closely with Northern on approvals for their selected routes.”
Certainly routes in the North West where new OLE is being erected, or where journeys are mostly under the wires, are likely future candidates.
Simpson adds: “The costs benefit model is interesting. Under the wires the pantograph can go up and the engine is switched off. In diesel mode, the engine is running at maximum efficiency through the existing traction equipment and is as fuel-efficient as a new DMU. Overall, you end up with a much more efficient train compared with running diesels under the wires.
“Track access is marginally more than an existing ‘319’, but comparable to a mid-life DMU. It is roughly the same weight as two ‘150s’ and should give a comparable track access charge. The fuel savings of only running diesel engines when you need them, and running them at a maximum efficiency, give a significant total energy cost saving when compared with a pure DMU option.”
Simpson explains that when running as an EMU the top speed for Flex is 100mph. She adds that, being conservative, when running on diesel it’s likely to be around 91mph-92mph. “Really detailed point-to-point analysis shows what it does well, and which routes and journeys will deliver the biggest benefits to operators,” she tells RAIL.
So how far has Porterbrook got?
“We have done all the concept design work, gauging work, and weight analysis, structural modelling, braking, journey time and performance calculations have all been completed,” says Isbern.
“Detailed design is now well under way. We know the suppliers we’ll use, and it is about getting into the details. The materials are ordered - we are really cracking on with it.”
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