Traffic on the 632 km Datong - Qinhuangdao heavy haul coal line increased from 123·7 million gross tonnes in 2003 to 150 MGT last year, according to Liu Zhengjie of the China Academy of Railway Sciences. He told the Railway Engineering conference in London on June 30 that this year the figure is projected to top 200MGT, which is double the route's original design capacity.

Following a sharp increase in rail failures, the jointed 60 kg/m rail on the coast-bound track was completely replaced by 75 kg/m CWR by the end of 2002. At the same time, heavier concrete sleepers were laid at a closer spacing. This year will see CWR laid on the westbound line used by empty trains, with wider use of in-situ flash-butt welding. Work is also underway to increase the depth of ballast, and improve the elasticity of the ballast bed.

Liu said the root cause of the increasing track failures was the lack of time available for maintenance, with pressure from growing traffic levels impacting on the scheduled maintenance windows.

A clear period of 180min per day was specified when the line opened, but this was cut to 140min in 1990. With failures increasing, the 180min window was restored in 2002, but for around 50% of the time 'this fails to be realised'. Work is currently underway to restructure the timetable, he explained, which will allow the operation of more trains over the line without impacting on the maintenance window.

A new maintenance regime is being introduced with regular tamping and ballast cleaning to ensure higher track quality. CARS is also looking at an optimised rail profile and the use of more resilient rail pads. Longer-term improvements will include realigning some sections at the mountainous western end of the route to eliminate the remaining 400m curves. The target is to standardise on the 800m minimum radius used on the majority of the line.

  • To handle the increasing traffic on the DaQin line, the Ministry of Railways has ordered 180 high-power twin-section locomotives from a partnership of Alstom and Datong Electric Locomotive Co. Awarded last October, the technology transfer contract is worth around €380m to Alstom. Derived from the company's Prima family, the 25 kV 50 Hz electric locos will have components sourced from France and Belgium as well as China. The first 12 locos will be assembled at Belfort, and the remaining 168 at Datong.