This is a how-it-works description for an Oyster rail journey. For the purposes of the description, no distinction is made between National Rail, Underground or DLR. They are all part of the rail network and one journey can include as many parts as you want. There is also no difference between what happens with different sorts of Oyster cards, be they adult, child, discounted or even staff. So, let’s get on with it:
Touch-in at the start
When you start a new Oyster rail journey there are a number of things which happen.
- The system checks to see if any refunds or online topups are waiting to be received. If there are they are added to your balance. Also any other instructions or travelcards are received.
- If your card has auto top-up enabled and if your balance is below the threshold it is increased by your auto top-up amount and a record made to be sent to the central system.
- Your balance is then checked against the minimum required fare for a journey from that station at that time. The minimum required can be zero if you have already capped for the day (or have a travelcard), or less than the fare if that would take you over the cap. If you do not have enough credit then you get a red light with two beeps and the gates won’t open.
- If you are ok then your balance is displayed* on the screen (unless it is an old gate on the Underground).
- The entry charge is then deducted from your balance (possibly making it negative) and a green light with one (or more than two) beeps occurs and the gates open.
Touch on a pink route validator
If you pass a pink route validator when changing trains at a station you are encouraged to touch on it. When you touch on a pink route validator, one of two things happens. If you are in the system and have not exceeded the maximum journey time from the start to the station with the validator then the location of the validator is stored in a via field ready to be used, if appropriate, at the end. In this instance there is no effect at that time on the balance or the fare for the journey so far. Alternatively the system starts a journey at that station by following the description above. This can happen if you have not touched in before (maybe the gates were open and you had a travelcard valid at that point, or you have used a paper ticket and touched the wrong validator), or if you have taken too long to get there. In this instance you do affect the balance and may also affect the overall fare. A pink route validator will NEVER end an Oyster journey.
Touch out at the end or at an intermediate station
If your journey is a simple one then this is the last section. If one or more OSIs are available then it may be repeated after the following section as many times as necessary.
- The system checks to see if any credits or products are waiting and actions them if necessary. Note that it will NOT try to add an auto top-up.
- It checks how long has elapsed since touch in at the start of the journey. If you’ve taken too long (or didn’t touch in) then it will discard any previous open journey and record an unstarted journey ending at that point.
- It works out the fare required to get to that station from the start, taking account of any travelcards held, any appropriate via points recorded and whether a cap has been reached.
- It adjusts the earlier deduction if necessary, but never by more than the previous entry charge, displays the new balance and the journey charge in brackets and opens the gate with a green light. Note that this even applies if your balance is now negative.
- The only exception is if your balance was already negative and an unstarted journey has been detected. In this case the gates won’t open and you will be asked to seek assistance.
Touch in to continue your journey
If your touch in completes a valid out of station interchange then the procedure is significantly different to the earlier touch in at the start.
- The system checks for any refunds or credits or products waiting to be received at the station and applies them if necessary. It will NOT apply an auto top-up, even if the balance is below the threshhold.
- Your previous journey details (up to the last touch out) have the price zeroed and the current journey is re-opened with the original start point.
- If the OSI is regarded as a via point then it’s use is logged in a via field ready to be used at the end if appropriate.
- Your current balance is displayed* (i.e. what was left after the last touch out) unless it’s an old gate.
- A new entry charge deduction is made, taking account of the fare charged so far. If that fare is at or more than the maximum journey charge then no deduction is made. You get the green light and the gates open.
Ticket Expiry or Low Balance warnings
* In addition to some old gates not being able to display balance information at all, there are some messages which over-ride the display of balance and fare paid. This is a problem on validators and some ticket gates. If you have a travelcard season (or bus pass etc) then a warning is displayed within the last 4-5 days of validity. Fortunately, most journeys made with a travelcard will not result in a fare being deducted so this isn’t too much of a problem. Since July 2013 however, a new warning has started to be displayed when the PAYG balance on the card falls below the maximum journey charge. This is not a good development because where it replaces the balance and fare you can be left wondering whether you have enough, or indeed whether something has gone wrong. All you can do is go to a ticket machine (possibly having to queue) to discover what your balance really is.