TRAIN length has long been considered one of the key limitations to improving the competitiveness of railfreight in Europe and despite some localised improvements in recent years, the pressures of running freight trains between passenger services on a network largely dating back to the 19th century has limited the potential for increasing payload.

However, there is increasing pressure to find a financially-viable solution. Freight trains are vying for capacity on key corridors with faster and more frequent passenger services. Furthermore, there is a need for rail to adapt to meet the increasing capacity of container ships, many of which can now carry more than 14,000 TEU. This creates a challenge for hinterland transport because only a small number of ports can handle such large vessels, putting pressure on road and rail infrastructure due to the increased number of movements from these locations. Longer trains will therefore be a necessity if the benefits of bigger ships are to be extended through the supply chain.

marathonIn September the conclusions of a €4.38m research project into the operation of longer freight trains on conventional mixed-traffic lines were presented at the InnoTrans exhibition in Berlin. Backed by the EU and 17 rail industry partners, the three-year Marathon project sought to validate the performance of 1500m-long freight trains running at up to 120km/h in everyday operating conditions.

As well as examining the technical feasibility of 1500m-long freight trains, the project sought to establish the economic impact of their operation and the potential efficiencies that could be generated. Marathon's target was a 40% cut in network capacity usage per tonne with cost reductions of up to 30% and 5% less energy consumption per tonne.

"Marathon is driven by the need to make better use of what we've already got," explains Marathon project coordinator Mr Franco Castagnetti. "No government has the money for major expenditure on railfreight infrastructure in the short-term, so we need to look differently at what we have now."

The Marathon operating concept is based around the coupling and splitting of two standard-length freight trains to optimise track capacity usage on busy freight corridors, using distributed traction to enable operation with a single driver. Conventional trains from two different points of origin converge on a freight yard, where they are coupled for the journey to a second yard. Here the trains are uncoupled and continue to their destinations as two or three conventional trains.

When the two trains are coupled, the inner locomotive or slave unit is controlled via a radio link from the lead locomotive, the master. The only additional equipment required for the operation of two trains in multiple is fitted to the locomotives and no modifications are made to the wagons.

Marathon says the installation of equipment on the locomotives was extremely straightforward and comprises just three main components:

  • a radio control unit (RCU) providing communication between the two portions of the train
  • a distributed power control unit (DPCU), which acts as a gateway between the two locomotives, and
  • a radio data transmission system.

The Marathon onboard equipment is compact, making it easy to fit, and there was no need for any modification or additional certification of the locomotives before they could be used in distributed traction mode. Furthermore, no additional man-machine interface (MMI) screens were needed in the locomotive cabs.

Following laboratory testing and economic analysis, the next phase was to test the concept on the main line. The first trial run took place on January 18 between Sibelin yard near Lyon and Nîmes, a distance of around 300km. Three regular Germany - Spain intermodal trains operated by Kombiverkehr were reformed into two 750m-long consists, which were coupled together at Sibelin to form a 1476m-long, 63-wagon, 3309-tonne consist with two 4.2MW Alstom class 37000 electric locomotives operating in distributed traction mode.

A second test train ran on April 12 when two 3.2MW Vossloh Euro 4000 diesel locomotives, again in distributed traction mode, hauled a 1524m-long 72-wagon, 4026-tonne intermodal train over the same route.

Both tests were deemed successful, with the trains travelling at over 100km/h on long stretches of the route, punctuated by braking sessions to test train stability under a variety of braking conditions. The tests proved that the longer trains were highly stable and longitudinal dynamic forces were found to be smaller than laboratory testing had indicated.

Crucially, in simulations and field trials Marathon demonstrated that longer trains could brake safely within standard stopping distances in all operational scenarios, and the project examined compressive forces across a wide range of different wagon types and train lengths. The Kombiverkehr intermodal wagons used on the mainline trials comfortably accommodated compressive forces of up to 400kN.

Coupling of the two trains was completed in less than 15 minutes in the first test and Marathon says this could be reduced to 10 minutes.

Marathon identifies the reduced demand for train paths and drivers as the key cost savings generated by longer trains, and while there are likely to be additional costs associated with linking two trains efficiently, these are considered to be small in comparison with the reduction in traincrew and infrastructure costs.

"Longer trains might require a different approach from shippers, but if we can tell them that they will share the benefits of this 30% cost reduction there will be a lot of interest," Castagnetti says. "I'm sure people will start to change their minds about rail as a shipping option at a corporate level if we can offer the market a system that offers real costs savings. For many companies this could be the beginning of an opportunity for modal shift to rail. Our partners decided to increase their spending on this because they believed they were doing something important for the industry. It is a solution that can bring important results to the market in a relatively short space of time."

While Marathon proves that running 1500m-long freight trains in normal operating conditions is technically feasible, the project team acknowledges that operating such trains on a commercial basis will depend on overcoming a number of infrastructure and operating constraints. Maximum train lengths vary widely across Europe, from just 450m in some parts of Spain to 575m in northern Italy and 750m in France, and the full benefits of longer trains will only be realised if train lengths are harmonised along entire international corridors. This is a key issue as the Marathon concept has been designed specifically for international flows.

It is likely that investment will be required in longer loops and signalling modifications, which may be difficult for some countries to fund entirely through their own resources. "There needs to be further study into the location of longer loops, whether it is every 200km, every 40km, or something in between," says Marathon project technical coordinator Mr Armand Toubol. "We also have to convince funders that the operation of longer freight trains will not have a detrimental effect on regional passenger services."

For the splitting and joining of trains at marshalling yards, punctuality will be vital. "For this to work in practice trains need to meet at the right time, and this could be an issue," Toubol says.

Longer trains will also require a very different approach to operations in a market where the emphasis until now has been much more on competition than collaboration. Castagnetti notes that partnerships have emerged in other sectors of the freight transport business to take advantage of potential operating efficiencies, and he sees no reason why this should not happen in rail.

SNCF, one of the participants in Marathon, has indicated that it could begin operating longer, heavier, and faster freight trains with distributed traction on a commercial basis as early as 2016. Marathon says that the short time to market proposed by SNCF demonstrates that the technologies used in the project offer the right level of security and maturity for immediate deployment on the railway.

Having proved that distributed traction can offer significant gains in productivity for both railfreight operators and infrastructure managers, the Marathon project offers considerable food for thought for the future of railfreight in Europe. While the technical viability of 1500m-long trains is beyond question, disparities in train length across Europe work against commercial implementation of the concept.

Furthermore, infrastructure managers will need to work more closely with operators, particularly across borders, to ensure the high level of punctuality that would be needed for efficiently coupling and splitting trains with multiple origins and destinations. Operators themselves will need to work together in unfamiliar ways to unlock the efficiencies of this method of operation. But if these challenges can be overcome, longer trains potentially offer a compelling solution to achieving modal shift to rail in Europe.