Comment 113926

By Haveacow (registered) | Posted September 21, 2015 at 09:49:05

One of the reason one car operation is avoided with new LRT operations is because of maintenance issues. If Hamilton is getting the Bombardier Flexity LRV (which seems likely), the operator, HSR is going to have to deal with a vehicle that has 3 trucks or bogies (the metal frame box that has the wheels). 2 of them are powered the centre one is not. The electric "Can" motors are mounted each side on the outside of the truck or bogie frame, 2 motors per truck. This allows quick and easy access to replace motors, the vehicle does not have to be separated from the truck and the frame raised by a hydraulic body frame jack. This process alone can take 30-45 minutes, the removal of the truck and the actual removal of the interior mounted electric motors by auto motive crane and jack. With most modern LRV's a single person walks up and tests the motor with a simple smart voltage/amp/resistance metre. It simply plugs into a free plug connected from the motor. If the motor needs to be replaced 2 plugs are unplugged and a power driver removes 4 pentagon shaped screws and bolt sets which, requires an expensive specialized head attachment (a security and a anti vandalism measure) and a simple but specialized pump truck is raised up into position and the old motor slides off and is slid onto the pump truck and it is taken away for service or disposal. A new motor is mounted on the pump truck and simply is slid into place. Screws reattached plugs plugged and you are done. simply test the new motor and bobs your uncle.

Single car operation has issues when a motor or drive system component breaks down while the vehicle is operating. If a single motor fails total engine output drops 20%-35%, the reason there is up to another 15% drop in available power is because of increased electrical resistance. With single car operation, this will considerably slow down the lamed vehicle and thus the entire line. With 2 car operation, there is by nature extra motor power available the loss of a single motor does not as severely effect the train. Thus the lamed 2 car consist has a much greater amount of power to draw on and will not as severly effect the whole lines operation.

Another drawback with single car operation is the tendency for a culture to develop in the operations areas to increase frequency instead of adding cars onto trains to add capacity. We have long told people that frequency can be the most important thing to attract ridership in transit operations however, with rail vehicles increasing frequency adds in much greater costs than a extra or extra set of vehicles in service. The need to add operators when decreasing frequency has big operational costs. Frequency up grades have significant maintenance costs to them as well. The disruption of the maintenance schedule of adding a extra vehicle or multiple car consist have the tendency to vastly increase maintenance costs. That's why with many US LRT operators its much cheaper to add another car to a consist to increase passenger carrying capacity than to lower the frequency. Sacramento for example has only one train every 15 minutes per direction on each line but as of September 2013, operated consists that are made up of 4 vehicles. There station platforms allow 4 vehicle trains and have since the late 1980's. In some cases a 5th vehicle is possible at some suburban stations. I do not know if they plan to increase electrical capability and the other station platform lengths to accommodate longer trains.

Keeping in mind that, electrical capacity is usually the hidden limiting factor in any rail system. The need to add extra transformers or increase the capacity of existing ones is often the most hotly contested thing about electric rail transit due to the environmental issues with the dialectric material in the transformers. Even with the newer wireless systems, you need even more transformers.

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