The TTC is expanding its proof-of-payment (or “POP”) system to streetcars operating along the 510 Spadina routes this Sunday, August 31.

You can board all streetcars operating along the route through all doors, with the start of service Sunday. However you must prove that you have paid a fare if one of the TTC’s new fare inspectors asks you to do so. A proof of payment includes a pass, transfer or POP receipt. An inspector may issue summons if you cannot produce proof of payment may apply even stiffer penalties if you are a repeat offender.

You can use new fare-vending machines and ticket-validators on board the TTC’s new low-floor streetcars, which also make their debut Sunday, or at the eight busiest stops on the route. If you’re riding an older streetcar, you continue to pay at the farebox, if you don’t have a Metropass or transfer.

Here’s how the fare-payment system will work on Spadina, starting Sunday:

If you’re boarding a new streetcar, you can use coins or tokens to buy a single-ride POP ticket from one of two on-board vending machines. Your must keep your POP ticket as proof of payment and for transferring to other routes or for entering subway stations. The POP ticket acts as a regular transfer ticket. You may also use an on-street vending machine to buy your fare before boarding.

If you’re a senior, student or child and you’re boarding one of the new streetcars, you must validate your fare at one of the two smaller, validator machines beside each fare-vending machine. The validator stamps the ticket and a stamped (or “validated”) ticket is your proof of payment and transfer. You then deposit the validated ticket in a farebox when you transferg to another TTC route. You also can validate your tickets at an on-street machine before boarding.

If you’re boarding the new streetcars with a transfer or pass, keep them handy as your proof of payment. Fare inspectors, and extra customer-service staff will help you with the new fare-payment process.

At a media event Thursday, we watched as TTC staff demonstrated the new vending machines, which took about nine seconds after the staff member inserted a token to issue a ticket. While that may seem like a long time, passengers will already be aboard and won’t be delaying other passengers boarding at the front doors when they pay their fares as is the case now. Streetcars will already be moving as passengers pay their fare and each new car will have two of the machines. Hopefully, many passengers will choose to buy their POP tickets on platforms, while they’re waiting for the cars.

The TTC estimates that about 60 percent of passengers boarding transit vehicles in Toronto use passes or transfers when they board, so only 40 percent of passengers may have to use the new machines.

In November, when the TTC starts to roll out the PRESTO fare-card system on its new cars, it will replace these vending machines and validators with machines that also accept the PRESTO card as a method of paying fares.

POP has been in effect on streetcars operating along the 501 Queen, 502 Downtowner, 503 Kingston Rd and 508 Lake Shore routes for many years. However, passengers can only use POP when the cars are operating along Queen Street, The Queensway and Lake Shore Boulevard West.

The TTC has proposed expanding the POP system to all streetcars by early 2015. This would eliminate confusion among riders as to when and where they may board cars by the rear doors.