Overview
One of the success conditions for modal shift from road to rail is that there should be a better "insertion" of freight trains on railway lines which also carry a significant volume of passenger trains. This particularly implies an increase in the speed and power of locomotives hauling freight trains, a reduction in pollution and lighter locomotive construction materials.
Several orientations of development can be envisaged for the future, notably a diesel solution or a turbine solution, each of which appear to have their advantages and drawbacks. The aim of this research is to select the most promising solution for a fast and powerful freight locomotive.
The objective of Elodit was to optimise the traction of a high-powered locomotive for freight trains on non-electrified railway lines. Given the goal of attracting new freight traffic to rail, the locomotive required should be of a higher specification than existing diesel locomotives.
The locomotive is planned as a Bo-Bo wheel arrangement, with 3000kW power at the wheels and 21 tonnes per axle. It is expected to cover 240 000 km per year and operate over 4000 hours per year.
Elodit is a comparative study between diesel motors and gas turbines. The analysis of the performances of these two engines is made according to a range of technical and commercial parameters: production costs and time, life-cycle cost, pollution and greenhouse gas emissions, impact on infrastructure, integration into train paths (acceleration), and potential markets in Europe and worldwide.
The analysis was carried out for a hypothetical mission profile as follows:
- trip from Rouen to Dijon (580km) with a 1600 tonne train;
- 240 000km per annum;
- 4 000 hours of operation per annum.
The conditions of use on the network will also be defined (operations, maintenance, ad-hoc infrastructure).
Funding
Results
Results for the journey example selected (Rouen-Dijon: 580km, with a 1600 tonne train) in terms of fuel consumption were:
- 7 854 kg of fuel for the Caterpillar diesel motor solution;
- 8 290 kg of fuel for the TM 1800 gas turbine solution.
The gas turbine motor however is likely to emit lower levels of pollution, between 20 and 80% lower than the objectives given by the International Union of Railways applicable from January 2008 (note UIC 624).
The turbine solution offers better reliability characteristics, due to the twin turbines. In the event of failure of one turbine, half of the normal power will still be available and this will in most cases allow the train to clear the track, complete the trip if traffic conditions allow this at a lower speed, or allow the locomotive to be taken without assistance to a depot for repair.
In terms of cost, over a 30-year life cycle, the turbine solution is cheaper. Including acquisition costs, the diesel solution comes to €2.85 per km and the turbine solution €2.66/km. Excluding acquisition costs, the diesel solution would cost €2.70/km and the turbine solution €2.38/km.
The overall conclusion found in favour of a gas twin-turbine solution, for the following main reasons:
- significantly lower maintenance costs;
- feasibility of a locomotive with a Bo-Bo (2+2) wheel arrangement, due to the lighter total mass of the locomotive (weight per axle 21.4 tonnes for the turbine option, compared to 23.6 tonnes for the diesel option);
- "redundancy" in energy production which would avoid the blockage of the track by the train and the need for a rescue locomotive in most cases of engine failure.
Only in terms of energy consumption does the turbine solution compare less well than the diesel option.
Policy implications
This comparative study was based on existing performance data and specifications of the motors involved. However a real demonstration would be needed in order to validate the choice of a gas turbine based solution for new freight locomotives.
Freight
The aim of this research is to select the most promising solution for a fast and powerful freight locomotive.
Rail
The objective of Elodit was to optimise the traction of a high-powered locomotive for freight trains on non-electrified railway lines. Given the goal of attracting new freight traffic to rail, the locomotive required should be of a higher specification than existing diesel locomotives.
The locomotive is planned as a Bo-Bo wheel arrangement, with 3000kW power at the wheels and 21 tonnes per axle. It is expected to cover 240 000 km per year and operate over 4000 hours per year.
Efficiency
Results for the journey example selected (Rouen-Dijon: 580km, with a 1600 tonne train) in terms of fuel consumption were:
- 7 854 kg of fuel for the Caterpillar diesel motor solution;
- 8 290 kg of fuel for the TM 1800 gas turbine solution.
The gas turbine motor however is likely to emit lower levels of pollution, between 20 and 80% lower than the objectives given by the International Union of Railways applicable from January 2008 (note UIC 624).
The turbine solution offers better reliability characteristics, due to the twin turbines. In the event of failure of one turbine, half of the normal power will still be available and this will in most cases allow the train to clear the track, complete the trip if traffic conditions allow this at a lower speed, or allow the locomotive to be taken without assistance to a depot for repair.
In terms of cost, over a 30-year life cycle, the turbine solution is cheaper. Including acquisition costs, the diesel solution comes to €2.85 per km and the turbine solution €2.66/km. Excluding acquisition costs, the diesel solution would cost €2.70/km and the turbine solution €2.38/km.
The overall conclusion found in favour of a gas twin-turbine solution, for the following main reasons:
- significantly lower maintenance costs;
- feasibility of a locomotive with a Bo-Bo (2+2) wheel arrangement, due to the lighter total mass of the