For the project EMD is retrofitting SD70ACe and SD70M-2 3.2MW locomotives, which meet US EPA Tier III emission standards, and will utilise parent company Caterpillar's Dynamic Gas Blending technology. A 45,500 litre ISO LNG tank, which is 12.2m-long and is fitted to a 48ft intermodal well wagon, will hold the LNG, which will be vaporised in the tender, avoiding the need for the cryogenic liquid to be carried across a coupler.

The ISO LNG tender can fuel either a single or dual locomotive formation and offer comparable power ratings and range to diesel-powered locomotives. Mr Brian Dracup, Wesport's senior director of rail, says this particular LNG project will have a 60-80% LNG use rate, and has the advantage of converting to 100% diesel if required.

Dracup says that adopting LNG could offer Class 1s a 30-50%, or $US 250,000 - $US 450,000 fuel saving per locomotive, per year based on average fuel consumption of 1.14 million litres per year.

EMD is expected to carry out stationary testing of the LNG-powered locomotive over the next few months ahead of CN's pilot line testing programme, which is due to begin this summer. Westport will deliver the three remaining LNG tenders by the end of the second quarter.

The low-pressure project is a companion project to the application of Westport's high-pressure direct injection (HPDI) technology to a SD70M-2 locomotive, which is supported by the Sustainable Development Technology Canada, a Canadian government-backed initiative which aims to commercialise emerging clean technologies. This scheme is again being developed in partnership with EMD and CN along with Gaz Métro Transport Metro Solutions (GMTS) and aims to provide a 95%-5% LNG:diesel fuel ratio.

Dracup likens the adoption of LNG to the conversion from steam to diesel locomotives in the 1960s, a view shared by leaders in the North American railway industry, including BNSF president Mr Matt Rose. Dracup expects the market for LNG tenders and locomotives to remain small scale in 2014-15 as initial pilot projects take place, but for these pilots to expand to orders for 25-100 units in 2016, and larger orders for 100 to 300 plus tenders in 2018.

He adds that in his opinion, due to the structure of a market in which only seven Class 1s now operate compared with over 100 during the steam era, that the widespread adoption of LNG could happen much faster than the 20 years it took for a complete switch from steam to diesel.

However, Dracup does not expect HPDI locomotives to be commercially available until at least 2017. He says that due to the average life of locomotives, retrofits to existing units will be more common initially before the adoption of locomotives built specifically for LNG utilisation.

"Dual fuel technology is the right technology in the beginning," Dracup says. "It is an interim technology designed to familiarise the Class 1 railroads with the new fuel to provide peace of mind before the major investment that will initiate the complete switch over. The risk-free demonstrations with dual-fuel locomotives that we are seeing now are intended for the railroads to get comfortable with natural gas, and to develop the infrastructure to accommodate it. When they have reached this point we will then be ready to enter with the HPDI technology."

For a detailed report on the development of LNG as an alternative to diesel in North America, including the regulatory issues facing the switchover, see the December 2013 issue of IRJ p32, or click here.