SkyTrain, Compass Card, and Redundancy

Yesterday, I was on BC 1 talking about the delays around the full launch of the Compass Card as this was the one year anniversary of the beta testing program. I finished the interview at around 4:45pm in Downtown Vancouver. Luckily, I just missed the major disruption to SkyTrain service yesterday evening, but the general timing was rather unfortunate. Though not as bad as the two system-wide shutdowns this summer, service was interrupted for about 4 hours on the Expo Line. As it turns out, it was a faulty modem that caused this latest interruption. Between a failed computer card, someone “knocking out” the power, and a failed modem, I have to wonder how redundant the system is. The SkyTrain system is extremely safe; when the system detects a fault, it shuts down. SkyTrain is a critical piece of our transportation system, so equally important is quick recovery from these faults.

While many have pointed out that the system is indeed aging, the equipment that has failed isn’t original to the system. It appears that TransLink is maintaining the system, but I wonder how redundant the actual design of the system is.

Would it make sense for TransLink to have two modems at each switch for problems like yesterday? Should TransLink have redundant computer cards to make sure that if one card fails, another will take its place in an instant? What systems could be put in place to reduce the risk of someone “knocking out” the power to SkyTrain control?

I work in broadcast television where 30 seconds of disruption is a big deal. When equipment fails, fast recovery is important. If one piece of equipment fails, another will pick up the slack. Sometime we even deliver the same content in parallel for redundancy. This redundancy costs money, usually about double the cost of a non-redundant system. While most television systems are redundant, we to have to weigh the cost of redundant systems versus the cost of failure. Sometimes having a redundant system doesn’t make financial sense.

Many people commented last night that the ~$200 million Compass Card program took away money from TransLink to make the SkyTrain system more redundant. The thing to remember about the Compass Card program is that it was a provincial project forced upon TransLink by former transportation minster Kevin Falcon. This money would not have been available for adding more redundancy to the SkyTrain system.

Ironically, it is the provincial government that has also forced TransLink to reduce costs. The first thing to go when reducing costs are redundancies.

TransLink has commissioned a report about the system failure around SkyTrain; the report is due out later this month. I look forward to reading it. Besides this report, it would be extremely useful to see a report on TransLink’s critical systems, what redundancies are currently in place, and what one-time and ongoing costs would be to increase system redundancies.

Of course adding redundancy to the system will require additional revenue. TransLink currently doesn’t have, nor is likely to get, additional revenue due to the impasse between the province and our region in funding transit.