Heathrow PRT



The last project I was responsible for in the UK was the new Heathrow PRT rail system. The rail system is a 3.8 km long raised steel rail.



The curved sections were complex due to the ac that the main box section members were fabricated from plate. Whilst in it not complex, the fact that he corners also changed in height as they rounded meant that the fabricated box sections were in effect helical. As the fabricator had heavily invested in CNC plate cutting machinery, I had to model the plates such that they could be ‘unfolded’ in Tekla Structures to provide NC files.



Personal Rapid Transit (PRT) is an innovative transport system which could provide a sustainable alternative to traditional bus and coach use at Heathrow.  It provides on-demand driverless travel using its own guide way network.


BAA will host the first commercial application trial of PRT in 2009 which will allow passengers to travel between Terminal 5's business car park (N3) and the main terminal building in individual driverless pods.



The PRT system under development at Heathrow is the ULTra (Urban Light Transport) system, which has been developed by Advanced Transport Systems Ltd, a company based in Bristol.


About the PRT system


ULTra, which stands for Urban Light Transport, is an advanced form of PRT which provides effective, low cost and sustainable transport for cities, airports and special developments worldwide.


The system works using a number of driverless vehicles which travel on a dedicated guide way network of 1.5m wide tracks which run at ground level or are elevated and can be routed within buildings making it much more convenient for passengers.



The vehicles are guided along these guide ways using laser sensors, which are embedded in the vehicle. The vehicles are powered electrically via a battery pack. The central control system ensures that batteries are recharged, as necessary, when the vehicles are stationary.


The access points and destinations chosen by passengers are a series of off-line stations which will be distributed around the network like bus stops or taxi ranks; positioned where they are needed. The passenger selects a destination and the central control system responds to this request by immediately allocating a vehicle on the required path and timing for that journey. The central control system also ensures that empty vehicles are sent where they are needed to meet passenger demand. Simulations demonstrate that waiting times are negligible, averaging around 12 seconds. 95% of passengers are served in less than 1 minute.



The vehicles automatically and non-stop, take the passenger to the desired destination on the best available route at speeds of up to 25mph. As a result, typical passenger times are reduced on average by 60% per journey and travel is more reliable, predictable and congestion free, affording passengers greater certainty in their journeys.


The vehicles are spacious with seats for 4 adults and ample space for shopping, pushchairs and luggage, with heating or air conditioning as required. Travel is safe and secure, with safety levels as good as trains, approximately ten times higher than automotive safety, and passengers have exclusive use of their cab and travel only with chosen companions.



The light, small and efficient vehicles, travelling non-stop and only on demand, result in significant energy savings and produce zero emissions at the point of use. The PRT system reduces carbon emissions by 70% when compared with cars and 50% when compared to trains and buses.