Going under with assurance

. Co-operation with the supplier, good design, good performance, right price and assurance of continued supply were all reasons cited by an experienced firm of engineers for choosing a leading maker as a source of bearings and other parts for new underground train inspection trolleys. Metronet Rail BCV, currently responsible for revitalising two thirds of the London Undergound system, asked Harmill Systems in Leighton Buzzard to develop a support system for workers as they moved along confined inspection pits beneath the trains in the Waterloo depot. Their concern was to reduce the risk of back injuries. The pits are only chest deep, and Harmill came up with a solution in which a chassis is mounted on wheels, riding on rails in the base of the pit. Across this chassis, two stainless steel shafts, held in place by shaft blocks, act as runners for four linear bearings which in turn support a small platform on which is mounted a 19 tonne bottle jack. A seat and seatbelt assembly ‘borrowed’ from a forklift truck completes the assembly on the top of the bottle jack. The seat can swivel through 360 deg and recline fully. Managing director and company founder, Patrick Hughes, told us, “We did quite a lot of research before we went to SKF for our linear bearings, shafts and other parts. They sent us samples of their bearings which we found to run really smoothly. Their design is neat and already incorporates tapped holes making it easy for us to connect to it. They gave us help with the design, and because we often work late, we found their web site very useful as a source of information out of normal office hours. Furthermore, SKF is a big company. We did not want to buy something which might suddenly be changed or cease to be available. The price was also good.” The train maintenance technicians are now able to sit in comfort and traverse the full length of the train (up to 60m in some cases) while also having full control of the side to side and up and down motion of the seat. According to Hughes, “The feedback we have had from the ‘train doctors’ as they are known has been fantastic. We understand that there is now an argument as to who does the inspection underneath and who does the insides of the trains. Before the trolley, the underneath was always the ‘short straw’, not now though.” Since its development, Harmill Systems has taken an order for another trolley that will run on wheels, and through word of mouth, and internal publicity within the rail companies, expects a number of further orders for similar devices as the rail companies address potential health and safety issues. The company, URL www.harmill.co.uk, has 30 years experience in engineering which includes: centralised vacuum cleaning systems, dust and fume extraction, heavy plant installation, compressed air, hydraulics, process pipe work, electrical and electronics, process controls, heating and ventilation, air conditioning and fire water tanks. Their choice of supplier is therefore made on the basis of long and extensive experience. In its turn, Metronet Rail BCV has taken over responsibility for upgrading, replacing, and maintaining nine of the twelve lines on the network and will spend £17 billion during its 30 year contract. During the first seven and a half years, some £7 billion will be spent on new trains, new track, new signalling and refurbished and modernised stations.