It often seems, when it comes to Toronto transit, that every silver lining comes surrounded by a dark cloud.

So it is with news about the St. Clair streetcar route. Starting in September, the TTC will be rolling out its big, new, accessible, air-conditioned streetcars on the route, which is fine news. At the same time, it will discontinue the two-hour transfer that has been available on that route since the right-of-way was built, which is terrible news.

In fact, the second half of that combination is the exact opposite of what the TTC should be doing. It ought to be expanding the two-hour-transfer rule across the entire system, especially as it goes to a fare system using the Presto card exclusively.

A bit of background, for those who may be unfamiliar: for most — soon all — of the TTC network, people can pay one fare for an entire uninterrupted trip in one direction, even if they have to change vehicles along the way. If they do need to change vehicles, they use a paper transfer to show they’ve already paid. (Those using Presto cards have the same rules apply, though they don’t need a physical transfer; their card is supposed to keep track and not charge them when they tap on the next vehicle.)

But riders cannot use their transfers (or Presto credit) for a return trip, and they cannot use it to hop off and then hop back on the same vehicle, either. Get off to grab a coffee and want to continue your trip? Pay another fare. Travelled two stops to the variety store, and now want to go back where you started? Pay another fare.

On St. Clair, the TTC has been in the midst of a semi-permanent pilot project for the past dozen years where different rules apply: instead of covering a single trip in a single direction, a transfer is good for two hours of travel on the St. Clair line. If you live near St. Clair, you can go to the grocery store, do your shopping, and return home, all on the same fare. You can hop off, visit a newsstand, hop back on and then get off at the café, then get back on and go to the subway. Or whatever you like. One fare is good for two hours of travel.

The time-based system is used in most other transit systems in the GTA and internationally, and is popular with riders. “The approach has been requested frequently by customers,” the TTC wrote in a report in 2014. With one notable exception, “all other aspects of a time-based transfer system would appear to be positive for both customers and employees,” the report further says. There’s a strong suggestion in there that this system would “undoubtedly increase the number of customer journeys.”

Win, win, win, win, win. That’s what a time-based transfer system represents for riders, for obvious reasons. It’s simple and easy to understand. It allows flexibility to do a little shopping, or to make a quick return trip. It gives you the freedom to get off a crowded car for a break, or to catch the next one. It’s a luxury that is already one of the great perks of having a Metropass — stopping off to buy a litre of milk on the way home doesn’t suddenly double the cost of your commute. And there’s no conceivable reason to think it’s fair to think it should.

And the thing is, the introduction of the Presto card makes it make even more sense. As a peer review appendix in that 2014 TTC report notes, the Presto system works more easily with a time-based system than with the existing convoluted one. At that time, three years ago, TTC executives were apparently expecting to go to a time-based system once Presto was implemented, and the peer review panel endorsed that expectation as a positive move.

Instead, the TTC is currently trying to have Presto enforce its current system. The result is that my Twitter feed — admittedly not a scientific survey — is constantly full of people complaining they’ve been dinged for extra fares because the system didn’t recognize their legit transfers. Simplicity is a virtue in itself when it comes to customer service, and it’s hard to get much simpler than “one fare lasts two hours.” Simple for the card-reader machines to track and understand, too.

So what’s the catch? What’s that one notable exception to the all-aspects-positive conclusion? Well, it would cost the system, the TTC estimates, about $20 million per year in lost revenue.

That may sound like a lot of money. I don’t have it available. But in the context of the TTC and city budgets, it’s relative peanuts compared to the benefits to riders. A 10-cent fare hike brings in $27 million. A 1 per cent property tax increase brings in about $25 million.

Things that improve the service cost some money, and they are worth it. Allowing kids to ride free — as the TTC started doing in 2015 — cost the system $8 million per year. But in the first-year of the policy, the number of kids riding transit doubled. That’s success!

The purpose of the transit system is not to maximize revenue by unfairly dinging passengers who want to ride it. The purpose is to provide a great service to riders that is affordable and convenient and makes life easier. Sometimes, if they do it right, achieving that goal costs a little money.

What did the TTC itself say about timed-transfer concept again? “Frequently requested by riders”! “Positive” in virtually every respect for “riders and operators”! “Undoubtedly” will increase ridership!

Something like that, you’d think they’d want to expand it so everyone benefits. Instead, they’re ending it in the one place they saw how successful it could be.

Edward Keenan writes on city issues ekeenan@thestar.ca. Follow: @thekeenanwire