LED technology adjusts output as ambient conditions change

Marl Sci-Light technology takes advantage of the controllability of LED lighting technology to adjust and supplement carriage lighting as ambient lighting conditions change. A 17W Sci-Light fitting replaces a 36W or 40W tube. Lighting is reduced to a minimum of 7W in daylight, ensuring that the carriage appears lit and welcoming to boarding passengers, and only turned on fully at night time or when the train enters a tunnel or other dark area. The trial is ongoing, but between February to May 2009, Porterbrook found that on average the lights normally drew between 15W and 21W (approximately a 40% to 60% saving).

Sci-Light relies on high speed sensors, and innovative control software using smart algorithms to eliminate spurious responses to temporary minor obstructions like trees, ensuring that passengers are unaware that the light level is being changed. According to Ian Walmsley, Engineering Development Manager at Porterbrook who approved the trial, “When travelling on the trial unit, the only way you can tell the light level is changing is by using a light meter. To the casual passenger, a constant, welcoming ambiance is maintained for the entire journey.”

“Porterbrook has led the industry with a thorough evaluation of this emerging carriage lighting technology that improves the ambiance for the travelling public, reduces energy consumption and saves operating costs. LED lighting uses less energy than halogen, and is now as efficient as fluorescent. It also eliminates the need to dispose of fluorescent tubes, which are classed as hazardous waste.” A further benefit is the reduced maintenance cost, said Ian Walmsley. “The lifetime of these lights is 10-15 years, making them maintenance free. They are also sealed units, which eliminates the time consuming task of removing dead insects from the diffusers.”

He estimates the potential energy saving as 2,000kWh per carriage or 20 million kWh across the network per year, if the technology is applied to all 10,000 rail carriages in use in the UK today. This equates to reducing CO2 emissions by 9200 tonnes and is equivalent to taking 3,300 cars off the road. The reductions in maintenance costs enhance the financial appeal of the technology.

Adrian Rawlinson, Managing Director of Marl International, said, “We are excited at the success of this major evaluation of LED lighting in the rail environment with one of the leaders in rail vehicle supply in the UK. Recent advances in LED technology have led to much greater light output allied to higher efficiency. LED has the potential to become the light source of choice for rail interiors.”

Susan Jacques, Managing Director of EAO, added, “Marl Sci-Light technology is an extremely attractive option, helping to reduce the lifetime installation and operating cost of new and retrofitted carriages. The energy savings and maintenance costs justify retrofit to existing carriages. LED lights are fit and forget – they are highly resistant to accidental or deliberate damage, and last as long as the rest of the carriage interior.”

The Class 323 unit involved in the trial is being used in normal service in the West Midlands area, operating from Birmingham New Street station. No adverse comments were received from the travelling public during the trial.