Street takes the train10 November 2010
Street Crane designed a control system for two cranes for a train carriage builder, allowing the cranes to work separately and in tandem, with very precise movements. Will North reports
Street Crane provided two overhead cranes to play a vital role at train carriage builder Bombardier’s Derby, UK, factory. The company is using them in the building of new Electrostar trains for London Overground, which will revitalise London’s rail commuter services. The cranes are used in the final assembly of the rolling stock, contributing to the safety and productivity of the streamlined production operations.
“Bombardier’s technically demanding specification required highly specified factory cranes that ensured safe, continuous and flexible working in an extremely intensive production environment,” explains Street Crane sales director Gus Zona. Two identical 20 tonne safe working load cranes have been installed. Each is fitted with twin ZX series ten-tonne hoists for assured lifting and handling. The cranes will be used independently during the assembly of the trains, but are designed for tandem operation when lifting and moving complete train bodies.
Zona says, “The cranes are used predominantly separately, so then they need their own independent control. There are only a few times a week when they have to be used as one machine. When they do, we need them to communicate together
“The cranes have to lift the carriage into position. They have to work in tandem and in sync to ensure that the carriage is lifted evenly and level. We used radio re-transmission to ensure the load is equal and level.
“They handle lots of different rolling stock, depending on who Bombardier’s customer is. The lifting criteria—the weights, length, lifting points—differ every time.
“We designed the control circuit in house. The sequence of events, the methodology, were put together by us, and the circuit prepared by our chief electrical engineer Colin Wild. We used a remote control from Hetronic, and an anti-collision system from Schneider Electric’s Telemecanique range “
Special on-crane safety equipment includes audible alarms as the cranes move up the workshop. Anti collision devices provide a safeguard when the two cranes are operated and moving independently. For tandem crane lifts and transportation a unified radio-based control system is used. This ensures the complete interlocking of overhead crane operations and total synchronisation of all movements.
To ensure efficient production, the cranes can transport loads at speeds of 40 metres/min in long travel down the 180 metre long workshop. Cross travel speeds of 20 metres per minute can be obtained and hoist speeds of up to four metres/min. All crane travel motions are under inverter control, using frequency inverters from Yaskawa, to ensure safe acceleration and deceleration for load stability and to provide precision low speed final placement.
Zona says, “We used variable frequency drives from Nord Drive Systems to control the acceleration and deceleration. You can very precisely programme the ramp of acceleration, so the crane can start at 0%, and smoothly ramp up to 100%, and back down again, eliminating load swing.”
Many of the Bombardier Electrostar trains have already been delivered and will service the London Overground to the north and east of the capital. Bombardier’s Derby factory is working a three-shift system to complete the order.