Dual-mode delight
RICHARD CLINNICK reports on why the new Class 88 dual-mode locomotives earned the National Rail Awards Train of the Year (Mixed Traffic/Freight) prize for Direct Rail Services
Why Direct Rail Services’ Class 88 dual-mode wins the National Rail Awards’ Train of the Year (Freight/Mixed Traffic).
Class 88s could revolutionise the way freight is hauled in the UK.
Their introduction last year proved such a success that operator Direct Rail Services collected this year’s Train of the Year (Mixed Traffic/Freight) accolade at RAIL’s National Rail Awards. The company collected the prestigious award at the ‘Railway Oscars’ on September 13, at London’s Grosvenor House Hotel.
Stadler built ten of the dual-mode locomotives for DRS, based on the freight operator’s successful Class 68 diesel locomotives. The ‘88s’ are predominantly electric locomotives, but feature a diesel option that offers far more than a simple ‘last mile’ scenario.
This means that while the locomotive offers full performance on electrified main lines but reduced performance with the diesel engine, it also eliminates the need for shunting locomotives in terminals. Its diesel engine also meets European Union IIIB emissions standards.
The Class 88 can haul trains in both diesel and electric mode, and the switch of power can take place on the move - much as with an Intercity Express Train.
It was designed to haul the heaviest intermodal trains while running at an increased speed, thus improving the environmental credentials of rail freight still further, while also offering faster journeys and greater capacity. Another benefit is that they offer metered electricity usage.
DRS says that the increased power and speed of the Class 88 means there is the possibility of intermodal trains running at up to 90mph in the future, compared with today’s 75mph. However, that would depend upon the availability of suitable rolling stock.
Much like the Siemens Class 700 that won the Passenger Train of the Year category ( RAIL 862), the ‘88’ is a modular design, based on the UK Light platform (Class 68) that has been adapted for use as a dual-mode machine.
The adaptable nature of this platform means that variants can be constructed for different uses, while maintaining commonality of parts and using the same principal certification/ homologation documentation.
Both the ‘68’ and ‘88’ have similar driving cab environments and locomotive systems that allow for easier traincrew training, maintenance technician training, and (ultimately) easier ongoing competency management.
That’s not to say that there weren’t issues. In its award entry, DRS states that adapting the UK Light design to the UK Dual meant overcoming various challenges.
These included: incorporating all equipment within the UK loading gauge; maintaining commonality of components with the ‘68’
(where possible) to allow the dual-power locomotives to be introduced as a ‘variation to type’; demonstrating pantograph compatibility for the whole of the UK rail network; and demonstrating network capability for the first electric locomotives delivered to the UK since the Class 92s in 1993. Where possible, DRS used the lessons learned from the introduction of the Class 68 into the design of the ‘88’. But what does the ‘88’ actually achieve? DRS states that for a modern rail freight operator in the UK, energy costs account for typically 20% of the total cost of operating a freight train. This includes electricity charges and fuel costs, and these need to be closely controlled. Using energy-efficient traction is a start ( be it diesel, electric or dual-power), as this can reduce costs, according to DRS.
In 2016-17, DRS spent about £ 5.4 million
on diesel fuel. It says that typically a 5% fuel consumption saving from using modern diesel-electric locomotives can save £ 270,000, while a typical 15% energy saving by using modern electric locomotives can represent a saving of £ 810,000.
It does state that savings are dependent on the relative prices of each form of energy, but even so there are a number of ways in which energy consumption can be reduced.
The first is via the design of locomotives with high power effiency (electrical and mechanical transmission).
Another is through regenerative braking on electric and diesel locomotives (the latter need to be fitted with AC traction equipment, such as the Class 68 and ‘70’). DRS says that the benefits of regeneration to the overhead line are dependent upon being able to recover cost savings, and that there is a need for simple energy metering or a billing system.
Another way is the optimisation of driving technique or style.
In terms of performance, the graphic (left) illustrates that over the Preston-Carlisle-Grangemouth section of the West Coast Main Line, the Class 88 will operate the same train for 15% less energy, while offering a 45-minute advantage over a Class 68 and an 80-minute advantage over a ‘66’. The first Class 88 arrived in the UK in February 2017, and was hauling a passenger train three months later. All ten were in the country by the summer, and in traffic soon after.
DRS says the ‘88’ passed through the Network Compatibility process and was placed into regular service quicker than other
current ‘new’ fleets, and with limited network testing. They are currently used on intermodal trains on the WCML, as well as nuclear trains ‘away from the wires’ to locations such as Sellafield and Hunterston, and Network Rail infrastructure trains over the Settle-Carlisle Line. The operator states that the intermodal trains are some of the most time-sensitive freight traffic operated on the UK.
In its NRA entry, DRS said: “Locomotives have operated on routes with the most challenging of topographies, and with significant performance risk, seven days per week for over a year. This is predominantly on some of the most congested routes in the UK.
“The gulf between DRS performance levels and any of its freight operating colleagues is now even greater than 12 months ago, and this is testament to how impressively the Class 88s have performed in their first year.”
As a result of the introduction of the ‘88s’, DRS claims it now has an A2F level (Arrival to Fifteen - the national freight performance measure), that is the envy of the UK rail freight industry.
The company stated: “It should not be overlooked that the bi-mode option has often resulted in reduced delays and resilience when network incidents have occurred where overhead line electrification has been compromised.”