Shifting freight transport from road to rail

Michal Sura 

In 2018, 25 % of total EU-27 carbon dioxide (CO2) emissions came from the transport sector (including international aviation) (1). CO2 is the primary greenhouse gas emitted through human activities and causes a global warming. The global warming is gradual increase of temperature of the earth's atmosphere. It is attributed to the greenhouse effect caused by increasing levels of CO2 and other greenhouse gases that are collected in the atmosphere, they absorb sunlight and solar radiation that have bounced off the earth's surface. CO2 emissions from transportation primarily come from vehicles powered by internal combustion engines operating on burning fossil fuel. If we want to reduce global warming, we should reduce the number of fossil fuel-based vehicles and increase the number of vehicles powered by renewable non fossil sources of energy. In the case of freight transport, we would achieve a significant reduction of CO2, when we shift a road freight to much ecological friendly railway transport mode.

A road transport accounted for 75.3% of the total inland freight transport in EU in 2018, followed by rail freight transport (18.7%) and inland waterways transport (6.0%) (2). There was electrified about 54 % of the EU railway network in 2016 (3), it means that approximately 10% of the total inland freight transport in EU was transported on electrified railways.

Rail freight transport consumes up to 9x less energy per tonne kilometer than inland freight truck transport. Trains are 4x more fuel efficient and they emit 75% fewer CO2 emissions (4) A double-track railway requires ? less land occupancy than four lane highway. As we mentioned above the shifting freight transport from roads to railways would the fastest and most efficient way to reduce a carbon footprint in transportation sector. 

But the shift a more freight from roads to rails will be not very easy job. Let’s mention some obstacles that limit this transition. For example the passenger trains have a priority over freight trains when it comes to access to railway infrastructure and they have granted a passage when it is necessary to clear a delay. A manager of rail infrastructure mostly wants all trains to book time slots in advance of their journey. These slots are often reserved over a year in advance of the trip. It is obvious that it is practically impossible guarantee a time of delivery in case of freight rail transport because the freight transport has almost always the lower priority. On the contrary roads don’t have any similar infrastructure manager who would need vehicles to book some time slot, the road vehicles can drive whenever they want. Road freight trucks do not have to worry about granting priority as all road vehicles are treated the same in case of access to road infrastructure. Trains pay for every single driven km on a railway while trucks pay only for some parts of a road they went through and sometimes they drive for a free, when they don't drive on toll roads. Another disadvantage for rail freight transport is a fact that the road network in EU is far bigger than the railway network, the railway density is only 1/20 of the road density. Trucks are able to deliver goods, almost whenever they want, they can provide door-to-door services very easily. 

The shift a freight from roads to rails is possible, but it requires a fundamental transformation of the railway freight sector. Infrastructure capacities, railway competitiveness, cost-efficiency and productivity must be improved to achieve this modal change. It requires extensive automation, digitization of the rail freight sector and development of new vehicles and implementation of new strategies if rail freight wants to provide agile delivery service. It would be good to develop logistics schemes like D2D (Door to door) or JIT (Just-in-time) delivery services. Since trains seldom provide D2D services, more efforts should be made to develop intermodal transport, a combination where a trucks or vans perform the first and/or last mile of a railway journey. Let's have a look at some innovations which would be helpful with mentioned shift.

A conversion from the manual world of screw coupling to automated railway operations with European Digital Automatic Coupling (DAC)

The most countries in the world have used some kind automatic coupling for a very long time. In European Union freight wagons are still coupled together with heavy screw coupling (except Finland and former Soviet republics of Estonia, Latvia and Lithuania where is used Soviet Automatic coupling SA3).

Coupling freight wagons using the screw coupling requires a hard work manual operation. An employee has to manually hang the heavy screw coupling between the wagons, tighten the coupling and separately connect the brake lines. Screw coupling takes a lot of time and it is pretty dangerous operation, because there were happened many serious accidents. Coupling and decoupling wagons often take place at night, so it is not easy to find employees for this kind of job.

Coupling and decoupling wagons often take place at night, so it is not easy to find employees for this kind of job.

With the current screw coupling used in EU is not possible to haul trains of over 5.000 t load (max. 3.500 t load during the starting in a slope of 12 ‰) without a risc to break the screw coupling. In case of using the UIC brake system, a brake pipe length of a train is limited to 750 m because of the physical limit in the transmission of pneumatic brake signal. Some EU countries even allow train length of 750 m, but in most of them it is around 450 m, because a limit of terminals, overtaking tracks, length of stations, marshalling yards, etc. In USA, South Africa and China are operated trains of length 2500 m and there in Australia trains have length 3000 m, that is five times more than in EU.

Digital automatic couplers (DAC) make all connections between freight wagons (mechanical, compressed air brake, electric and data lines) without a human intervention. 

It is in contrast to world widely used automatic couplers which only make a mechanical connection, there is necessary to connect brake and electric lines in the most cases manually. It is obvious that digital automatic couplers make coupling much faster and easier and it is a big step ahead

With digital wagon coupling would be possible work together on the automatization of wagons coupling and digitization of freight transport. If a locomotive and towed wagons were equipped with sensors, there would be possible to have a lot of information what goings on in case of hauled rolling stock, because a connection trough data cables allow them to exchange data. Let’s have an example how data exchange would be helpful in a case of driving train operation… nowadays a train driver in a locomotive does not have any idea what is going on with the hauled freight wagons. If some wagon derails and the train driver notices it after one or two minutes, the derailed wagon would caused several million EUR in damage to a railway infrastructure. A scenario like that is still possible to happen even nowadays, because there does not exist any data communication between the wagons and the locomotive. If there were installed suitable sensors on the wagons which would indicate a derailment, it would possible to avoid major damages. DAC allows to make the data connection between the locomotive and the wagons, because there will be coupled data connectors together also beside the mechanical coupling. 

There was set up consortium known as DAC4EU which consists from six public and private freight transport companies RCG (Austria), DB Cargo (Germany), SBB Cargo (Switzerland), and the freight wagon leasers Ermewa, GATX Rail Europe and VTG which will be testing different digital automatic couplers over the coming years. The consortium is led by Deutsche Bahn AG. The pilot project was awarded by The Federal Ministry of Transport and Digital Infrastructure (BMVI) for around 13 million Euro, the project started in July 2020 and will finish in December 2022. The aim is testing digital automatic couplers suitable for freight wagons. A dozen freight wagons received four different types of automatic digital couplers and they will be tested for two years. A train of 24 wagons tests the technology which is verified in the real operation. Four manufacturers are currently developing a DAC couplers. 

The goal is to introduce digital automatic coupling throughout Europe.

The digital automatic coupling offers these advantages:

• automatic coupling and decoupling of wagons
• faster and cost-effective providing of freight transport service
• monitoring of freight wagons by sensors 
• reducing labor costs 
• trains with a length of more than 750 meters and a train weight over 5000 tons would be possible to operate in EU 
• allows larger capacity of freight transport

Challenges for migration from the manual world of screw coupling to automated railway operations with DAC

• it is necessary to convert between 432,000 EUR and 485,000 EUR freight wagons and 17,000 EUR locomotives in EU 27 plus CH, NO, UK
• the conversion per freight wagon would costs 10,500 - 12,500 EUR and 25,000 EUR per locomotive
• the total conversion cost of freight wagons and locomotives is estimated between 4.7 and 6.2 billion EUR
• the conversion should be completed in 2030

Bimodal locomotives powered by energy from electric accumulators or diesel engines for the last mile solution

The rail freight stations or combined transport terminals where handling cranes operate cannot have any obstacles like electric lines above them for a safety reasons, so railways in such places cannot be electrified by overhead traction wires at all.

In places like these an electric long distance locomotive has to be decoupled from its wagons and a small diesel railroad locomotive called shunting locomotive is used for manoeuvring by these wagons inside a rail transport terminals. The shunting locomotive in not intended for moving trains over long distances, but just for assembling wagons for a long distance locomotive. When the capacity of these shunting locomotives is not used sufficiently, the cost structure of rail freight transport becomes inefficient.

A possible solution would be using bimodal locomotives, suitable to haul a freight train over long distance with electric power from overhead traction lines and suitable also for shunting services in not electrified freight terminals or in marshalling yards.

An example for an electric locomotive with “a last mile package” is a locomotive Traxx AC3 Last Mile produced by Bombardier Transportation and a locomotive Siemens Vectron Sr3 "Last Mile Diesel". These electric locomotives are equipped with a small diesel engine with cca. 200-400kW power which allows driving a heavy freight train on non-electrified lines at low speed 40-60 km/h and provide the shunting operation on their own, so they would not need need using any shunting service provided by a special shunting locomotive. It would save money a time, of course.

A consortium “Future Freight Locomotive for Europe” has an aim to go a step further by replacing the emission producing diesel engine by full electric last mile propulsion system, based on Li-Ion batteries, with up to 500 kWh energy and higher peak power in the range of 1MW, occupying the same space in the locomotive as the last mile diesel engine. It will bring the innovation to a next level, because it will be possible to drive heavy freight train on short non-electrified lines and to enter areas where is required low noise and zero exhaust emissions. Plus the electric Li-Ion batteries will allow to recuperate large amounts of braking energy and reduce the overall energy consumption.

Locomotives with added the last mile functionality offer these advantages:

• the rental service of shunting locomotives at freight terminals will no longer be necessary. (however, freight terminal authorities may forbid entry with locomotive due to a safety concern or they would charge entry fees to compensate losses for not using their shunting service)
• the quick accessing to railways in industrial sites for loading or unloading a freight
• the freight trains would make a short stop at the stations with side tracks where mobile cranes would transfer selected containers between trains, trucks or temporary storage site 

An alternative freight train conception - light freight train

The CargoSprinter is a railway freight multiple unit designed to transport freight. It was developed in 1996 by Windhoff together with cargo operators DB Cargo and Fraport. CargoSprinter consists of two motorized front and rear control cabins with five wagons (container platforms). The ends of CargoSprinter are powered by Volvo diesel engines (265 kW) and it allows to CargoSprinter can move on electrified and not electrified railways. The wagons are permanently coupled during a service. It is very interesting feature that CargoSprinters can work in multiple forming which consists of up to 7 trains, 35 wagons (630 m long). It is possible to make the formation from several CargoSprinters which are located at different loading stations before they come together and form one long train, coupling CargoSprinters together takes very short time, it would be done in minutes. As we can see it is not necessary to do any decoupling and shunting operation, it is very easy to form a "train" which carry freight to the final destination. 

CargoSprinter can run at high speed (up to 120 km/h) as fast as the most of passenger trains, which allows to CargoSprinter to move on railway tracks without much impact on the movement of other trains. But passenger trains have priority over freight trains in a case of railway access. For reasons of planning and safety, a manager of rail infrastructure requires all trains to book slots in advance of their journey and these slots are often booked over a year in advance of their trip. A political decision was made to give passenger trains priority, because it is best to keep passengers happy. If this political approach would be possible to modify or change, rail freight transport could compete a bit more with road freight transport and providing "just in time" rail freight delivery will be more realistic.

CargoSprinter has a big advantage over common freight trains in case of express delivery for sure. CargoSprinters are more suitable for the smaller freight-shipments, for spontaneous and fast transport. Using of such self-propelled bidirectional trains would be an alternative to road freight transport in some special cases. 

In a practice the CargoSprinter was not very successful as a commercial freight vehicle in late of 1990’s and early of 2000's, this concept was more successful as an infrastructure and services train.  

CargoSprinter is very good concept which was a way ahead of its time of introduction, but its drawback is using diesel powertrain. Diesel engine emits CO2 and if we want to reduce a carbon footprint, it would be better when a CargoSprinter or similar concept is equipped with electric motors which would be powered by electric energy collected from overhead rail lines and from a Li-ion battery pack to have "last mile" functionality in case of access to non-electrified rail sidings or rail freight terminals.

This concept offers a change in rail freight transportation, allowing rapid transport of freight transport which is less than full trainload or short line freight.