From today, you can use your contactless credit or debit card to “tap on” for Sydney and intercity train services.

Commuters can pay for their fare using most American Express, Mastercard and Visa credit or debit cards; or a smart device linked to one of these cards. Just make sure you tap on and off with the same card.

The new contactless payment system is a handy back-up for those days when you’ve forgotten your Opal card, or get caught out with the dreaded red “balance too low” message at the barriers.

The catch? Your card will be charged at the standard, peak adult fare – which means even if you travel in off-peak times, you’ll be charged the full adult fare; and no concession fares are available through the contactless payment system.

Additionally, contactless card users won’t reap the usual Opal card benefits, such as weekly travel rewards and transfer discounts.

If the same contactless card is used often enough in the same week, though, the Opal daily, weekly and Sunday travel caps will apply. Additionally, a full adult Opal fare is cheaper than the “single trip” paper tickets dispensed from Opal ticket machines – for a Marrickville to Central trip, it could be the difference between paying $3.54 with your credit card, or $4.40 for a single-trip ticket.

The rollout of contactless card payments on train services follows successful trials on light rail and ferry services.

According to the Sydney Morning Herald, contactless payments for bus services are slated for mid-2019.