MW generating sets. The turbines' blades are long each and when the turbines spun at their usual fixed speed of 3,000 rpm, the outermost tip of the last row of blades travel at approximately 2,000 km/h. The boilers operated on pulverised coal and delivered 844 kg/s of steam at 158.6 bar and 566 °C. In the financial year 1980/1 the station sent out 5,285.937 GWh, the thermal efficiency was 33.13 per cent. The station used low NOx burners and electrostatic precipitators to reduce its environmental impact. The majority of the station's ash waste was sold to the construction industry. Electricity output The generating capacity and thermal efficiency were as shown in the table. Coal supplies and rail access Until June 2010, approximately 3000 – 6000 tonnes of coal was delivered to the power station every day, via a branch line railway through Madeley, Ironbridge and Coalbrookdale, crossing the River Severn via the Grade 2 Listed Albert Edward Bridge. The railway branch joins the Wolverhampton to Shrewsbury line at Madeley Junction. Coal was delivered variously by DBS, Freightliner and Fastline. After the trains were emptied, they were usually stabled at Warrington Arpley Yard. From 2014 until closure, an additional three trains per day were worked by GB Railfreight from Liverpool dock with biomass chips, which were the main source of feedstock for the power station by then. Scheduled passenger services on the branch line were stopped in the 1960s, and so the line was kept open primarily for the transportation of coal to the power station. A steam locomotive-hauled special passenger train, organised by railtour company 'Vintage Trains', visited the branch line on 3 November 2007. The tour was entitled Pannier to Ironbridge, and was hauled by former Great Western Railway 0-6-0 Pannier tank No. 9466, which ran a return trip between Tyseley, near Birmingham, and Ironbridge. Ownership In 1990 the CEGB was split into different companies for privatisation, and Ironbridge Power Station went through a number of ownership transfers before eventually being owned by Powergen. In 2001 Powergen was taken over by E.ON, an energy company based in Germany. The station was the last major generator of electricity in Shropshire. The plant consumed about 1.2 million tonnes of coal and 20,000 tonnes of oil each year, and generated 2,990 GWh of electricity in 2004. Environmental group Friends of the Earth claimed in 2006 the station was the second worst polluting