LRV designs
Sir - Having read your latest issue regarding light rail transit activity on the West Coast of North America, I found that William D Middleton gave an excellent overview of the present situation.
Unfortunately, however, he seems somewhat less well informed about available light rail vehicles for the proposed systems. His inference that an LRV, such as the ’high speed’ Portland car, would be the preferred choice should be re-examined as a speed of 90 km/h can hardly be described as high. This vehicle was designed to comply with the arbitrary ’2g’ buffing load requirement and run in consist with an existing high-floor car with the same buffing strength. The resultant vehicle is nearly 14 tonnes heavier than what is really necessary for a new light rail system which is not constrained to meet this requirement. Crash management techniques, which are well known in Europe, are producing much more efficient and safer designs for passengers.
There are several excellent 70% low-floor designs available off-the-shelf in Europe, all of which are around 36 tonnes at the AW0 stage (vehicle ready for operation but no passenger loading). These designs are very pleasing from an aesthetic standpoint, both inside and out, much more so than the Portland or Hudson - Bergen LRVs. In addition, as a result of the lighter weight, the propulsion efficiency is much better. The electrical energy cost saving over a ’2g’ low-floor LRV of the type suggested would be very substantial over the life of the car - one transit authority spent over $20m on power alone last year. In the age of global warming, this aspect of transit operation must be considered, especially when it is the taxpayer who will be footing the bill.
N C Halden CEng, MIMechE, PEng(CAN)
Princeton
New Jersey
USA
Don’t bank on it
Sir - Unfortunately, the required disclaimer to my recent article on infrastructure separation in Rail Business Report 1998 was inadvertently left off the published version.
For the record, the article should have included the following statement:
’This article represents the views of the authors and not those of the World Bank, its affiliated organisations, or members of its Board of Executive Directors or the countries they represent.’
The article in no way necessarily reflects the views of anyone other than the authors: any inference to the contrary would be unwarranted.
Louis S Thompson
Railways Adviser
The World Bank
Washington DC, USA
