SkyTrain – What TransLink Is Not Telling Us
This reply from Haveacow who is an Engineer, to an earlier post and I think worthy of a post on its own. He is familiar with SkyTrain and worked on the Ottawa LRT and inn other words he knows his stuff.
Despite the ‘huff and puff’ from high paid TransLink spokes people about how the new SkyTrain cars will increase capacity, the system is presently at capacity until ” $500-$800 Million on really upgrading the electrical systems”.
Again, I must remind everyone, despite being on the market for almost 40 years, and with unprecedented hype and hoopla in the local and international media in 1986, only seven systems have been built; no new SkyTrain Line (the evergreen Line is the unfinished portion of the Millennium Line) has been built in ten years and no SkyTrain has ever been allowed to compete against light rail.
A historical note: Intermediate Capacity Transit System or ICTS, was first billed to fill the gap of what a Toronto PCC car could carry (pairs of PCC’s on Toronto’s Danforth-Bloor route were able to obtain a peak hour capacity of 12,000 pphpd or about 2,000 pphpd less than Vancouver’s Expo Line) and the minimum capacity that would require a subway (15,000 pphpd).
The modern articulated car, operating in coupled sets effectively made SkyTrain obsolete overnight; that is, if one wasn’t already operating one.
and able to obtain a peak hour capacity of 12,000 pphpd!
Beyond the power supply issue that will forever haunt Translink until they are ready to drop somewhere between $500-$800 Million on really upgrading the electrical system’s actual carrying capacity, increasing by somewhere to around 50-60% the number of power blocks or better yet, doubling the number of existing power blocks. Translink has to rethink the basis behind the Skytrain way of doing things.
To make it simple, the basis behind the concept of the Light Metro Systems or Intermediate Capacity Rail based Rapid Transit technology is the basic notion that by decreasing the frequency or increasing the tempo of rail operations you can use smaller vehicles and stations thus, saving money when building infrastructure but still have higher capacity because of the higher levels of service. This basic operating assumption is at the heart of all Skytrain’s troubles. One of the reasons LRT technology has been so easily surpassing the Skytrain’s technology is because it doesn’t make assumptions about the operating system an environment needed to have the it working. It just tries to adapt it to fit as many varieties of operating environments and operating technologies as possible. Automation was added to the Light Metro System to increase the financial savings needed to offset the high cost of high tempo railway operations. The linear Induction Motors used by the Skytrain were chosen because of the lack of moving parts thus its believed, easier maintenance compared to the standard electric motors especially the motors of the time when the system was being designed and tested (70s-to mid 80′s).
Although initially the Induction motors saved some money compared to electrical motors on rail systems of the time. Much newer, smaller, more durable, cheaper and more powerful standard “Can Motors” generally used now in transit based electric rail operations are significantly easier to work with than Induction based systems. Induction motors still have some advantages when it comes to rail operations that have a greater distance between stops on very high capacity lines but they are very poor accelerators. When station stops are less than 2km’s apart there is a great deal of time lag compared to standard flywheel based electrical can motors. The flywheels can dump extra power into the motor at start up, to help more quickly overcome inertia. These motors last just as long and sometimes, much longer than Induction based motor components. The positioning of the motors on the side of the bogie or truck eliminates the needs for axels but space can be provided if bigger grades require the need to further arrest “Flange Slip” or Wheel Slip. The side mounted motors allow for the “U” shaped bogie or truck frame needed for 100% Low Floor Vehicles. Maintenance is very cheap because a single person with simple commercially available equipment and hand pump forklift dolly can in about 5 minutes test every electrical motor on a standard LRV and replace all of them if needed in 30 minutes with out assistance.
The Skytrains have a monitoring system which identifies Induction units with failing components. Unfortunately testing of the individual components is difficult unless the whole vehicle is brought in to the maintenance track, where a crew of 2 or 3 is needed to bring in any Skytrain Vehicle detach, separate and lift the frame of the vehicle from the bogie or truck, then test each external component of the induction drive. Then, if replacement of the main drive unit is needed and it usually is, a specially adapted automobile hoist is brought in to lift the drive unit or other non performing part out from the centre of the truck or bogie. A replacement is then lowered slowly back into the frame and reattached. This whole procedure can take over an hour for each unit being replaced with a crew of 2 or about 40 minutes with a crew of 3.
The high tempo of Skytrain operation means time is always short and great emphasis is placed on having to maximize maintenance efficiency thus the costs for these activities become very high. Preventive Maintenance has to be done more often because of the need to constantly have a greater percentage of your train fleet in operation means that, mileage targets get hit faster than with other types of systems like LRT and general maintenance checks have to occur by law much more often. This stresses maintenance staff a lot, when they have to admit that there masters and managers that there aren’t enough trains operating due to the fact that, there is backlog of trains waiting to complete there 1000km or so mileage PM check, which is mandated in your operational certificate for these types of rail vehicles by Transport Canada. I now for a fact that has happened on your system a few times in the past.
(A comment from Zwei: maintenance costs are also higher because the trains need to be at 100% because if a train fails, the entire system stops until a worker walks out to the failed train to drive it to the nearest station and/or siding.)
The Induction motors also require a piece of track infrastructure a 4th rail, or induction rail, that has to be kept debris and ice free for the system to operate. Improperly mounted induction propulsion units caused by damaged frames or improper placement during maintenance increases the distance the unit must be from the induction rail. This distance must be constant or the train won’t move.
(A comment from Zwei: The ‘air-gap’ or the distance from the reaction or 4th rail and the LIM is 1 cm and if this critical distance is not maintained, power consumption increases dramatically if the distance is increased or scoring of the LIM happens if the distance is less. Also keep in mind that throughout the lifetime of the track, wear by the trains can account for a 1 cm loss of rail height and it is cheaper to replace the rail (which has happened twice now in 30 years) than constantly adjusting the reaction rail.
As Mr. Cow stated, the LIM’s are very expensive piece of kit and the original advertising stated that they should be only used on routes with steep grades, as LIM’s were well suited for the task.)
This extra piece of track is responsible for almost 35% of the track maintenance budget at Translink. The Induction Motor used to be standard part of the Bombardier Innovia Automated Light Metro transportation System (Skytrain’s official marketing name at Bombardier) but is now an option. The latest Innovia System instillation designed for Saudi Arabia doesn’t even use the induction motor but standard electrical ones and a different body type designed by a local Saudi contractors, allow the platform mounting and frame are Bombardier designs.. You wouldn’t even recognize it as a Bombardier product.
Although a 3rd rail does have advantages in high tempo operations, it has very high operational and maintenance costs associated with them compared to overhead wire power collection methods. The use of 3rd rail forever means that, even if the technology greatly changes and future designs of Skytrains allow for low platform boarding and or low floor vehicles, you will never be able to run it on a street level right of way because of the 3rd rail power collection method, thus always having higher build and design costs compared to low platform and low floor operating technology equipment.
The Automation technology used, Bombardier’s CityFlow 650 System (also not being used in Saudi Arabian operation by the way) means that under Transport Canada rules, a street running right of way is illegal and thus a physically segregated and most likely a grade separated right of way must always be used. Yes, here in Ottawa we will have a certain level of automation on our physically segregated rights of way for our LRT as well. However, this is because the right of way was already physically segregated when it was a Bus Transitway, it was designed that way also to be convertible to rail technology in the future. However because our LRV’s will have drivers we can operate and are planning to operate on the median of streets like Carling Ave. for the Stage 3 program deployment in 10-15 years. All the appropriate usable Transit-ways by this time, will be used for LRT and the remaining Transit-ways will still operate buses.
Lastly, the capacity of Light metro is highly effected by many of its component technologies and thus has to operate trapped by the limits of its operating agenda. Where as LRT has no pre decided operation type and thus can be made adaptable for many operation options. The Skytrain was billed as something that was cheaper than a subway and able to move more passengers than LRT. However, the limits put on it by its pre packed operation type means that it hasn’t been that adaptable over time or as it turn out quite ironically, not that scalable either, which was one of its original claims. Edmonton now operate 5 car LRT consists that are almost 125 metres long. Calgary’s LRT is now operating 4 car consists up to 111 metres long. Ottawa’s LRT will start at 2 car consists that are 98 metres long and can be easily expanded by adding a 5th section to both cars in the consist and increase the length to 120 metres. All these system were able to add capacity without altering the schedule and hiring an extra driver and forcing up its operating tempo, helping keep a lid on costs. Vancouver’s system has no choice but to greatly increase its frequency because the concept behind your Skytrain limits physical expansion as an option by having to operate in very expensive rights of way, unless a truly massive amount of money is spent to scale it up.