In an ideal world, if you want to travel by train from A to B to C back to A, you can buy a ticket from A to B, then B to C, then C to A. However, by doing so in Great Britain, more often than not you will pay much more than people doing return journeys, A-B-A-C-A despite that the distance is much shorter.

This is because of a historical artifact which effectively penalising off-peak single journeys. In the long, distinct past, when the railways in Great Britain were still British Rail, there was only one fare for each journey – the single fare. Later on, a fare type called “Cheap Day Return”, which is called “Off-Peak Day Return” today but the code remains as CDR, was introduced to encourage days out by train, by offering return tickets for the price of a single (now usually 10p more than a single as there were complaints about a return ticket being offered when a single was requested).

Because most journeys are return journeys, as a result, those not travelling on a return journey is effectively penalised, for example, those making a single journey, an open jaw journey, a triangular journey, those going out by train and returning by coach, etc. For some open-jaw or triangular journeys, it is possible to buy a return to somewhere inside the open-jaw or the bottom of the triangle with a ticket of “Any Permitted” route, but if the triangle is large enough, and there isn’t a calling station at the bottom of the triangle, this may not work at all.

The last weekend I made a journey from London to Guildford, then to Brighton back to London. Plotting this on a map, it looks like a triangle with a tail hanging down.

The triangle is formed by London – Guildford – Redhill as the 3 corners. A London – Guildford return ticket is not valid via Redhill, and a London – Redhill return ticket is not valid via Guildford. There are only 2 intermediate calling points for a fast train from Guildford to Redhill, which are Dorking Deepdene and Reigate, and the return tickets from London to both are not valid via Guildford as well, so there are no return tickets which allow me to travel this triangle. If I buy singles for the triangle along with a return to Brighton, I will pay much more compared to going back to London and out again, which I don’t want to.

However, despite the above, there is a way to buy a return ticket to travel on this route. The catch is that you must have a Travelcard. The ticket is called a Boundary Zone ticket. When you hold a Travelcard for Zones 1-6 (or a Freedom Pass, 60+ Oyster), you can buy a ticket which has the words “Boundary Zone 6”, or “London Boundary of Zone 6”, as the origin or destination instead of a station. The human-facing documents are silent on what routes can these tickets be used, as they only define the routes between two stations (“Boundary Zone 6” is not an actual station), so it is open to interpretation. However, the document RSPS5047, which contain the rules for accreditation for ticket retailers in terms of route checking, specifies how these tickets are validated for the purpose of issuing tickets in combination with an itinerary. For tickets like these, the rules are specified in section 9.2.2, “Application of the routeing guide to zonal fares”. The fare I am interested is called Boundary Zone 6 – Dorking Stations (Dorking Stations is a station group which consists of Dorking (Main), Dorking Deepdene and Dorking West), with route “Any Permitted”, so it is a journey where the destination is outside the zonal system, specified in section 9.2.2.6. It says that

For journeys which terminate outside the zonal system, where the fare origin is zonal, the Rail part of the journey is validated, from the last relevant station inside the zonal system to the destination. The last station pass/stop event which is in one of the zones covered by the zonal fare is the relevant station. The part of the journey from this station to the journey destination should be validated using NRG rules. ll other pass/stop events in the journey must be included in the zones covered by the zonal fare origin.

For this journey, if I choose Surbiton as the relevant station, the part of the journey from Surbiton to Dorking Deepdene is valid via Guildford because it is within 3 miles within the shortest route. According to the electronic data, the shortest route from Surbiton to Dorking Deepdene is Wimbledon, Streatham, East Croydon and Redhill, which is 31.00 miles, while the route I wanted to use, which is via Effingham Junction and Guildford, is 31.08 miles, therefore it is valid subject to easements, and there are no easements disallowing the use of this route. While on the return journey, I choose Coulsdon South as the boundary station to cover my travel from Dorking Deepdene to Redhill.

This ticket is priced by South Western Railway and the price is only £3.30 return after railcard discount, between the prices from Ewell West and Ewell East, the most direct routes between London and Dorking. However, as the route is Any Permitted, there is no prohibition in choosing other boundary stations as appropriate where the standalone fare is more expensive. This is one of the advantages of using a Travelcard – to travel out and back into a different station covered by the zones using a return extension ticket.

Trainsplit Beta can now sell Boundary Zone tickets by specifying the kind of Travelcard you already hold. It works slightly differently to the specification above – it checks the route from the last calling point instead, ignoring stations which are passed non-stop. Therefore, I entered a search from London to Dorking Deepdene, specifying Surbiton as a calling point on the outward journey, and Coulsdon South on the return journey, and obtained my tickets.

I also needed to buy a Travelcard, which can be obtained at Trainsplit as well in the same order by adding a new journey before the checkout, entering any one station in Zone 1-6 as the origin and the words “London Travelcard Zones 1-6” as the destination, to make it clear in case of customer support, however such ticket bought online needs to be obtained at a National Rail station with ticket collection facilities, which I would not use before my journey as my journey will start at a London Underground station, which cannot be used to collect tickets, so I bought the ticket from the station instead.

By using these tickets, I could avoid the “single-journey penalty” for my travel where a regular, point-to-point return ticket is not available.

Hopefully, the fare reforms are now taking place to remove the need of complicated ticketing options for such journeys. Project Oval has reduced single fares to be half of the return fare, ending the single-journey penalty, and unified peak / off-peak times to a common standard in its area. Guildford and Dorking aren’t in the area yet but they are planned to be included in a future expansion, by then I can buy my tickets in a normal way without paying extra: one ticket from London to Guildford, one from Guildford to Redhill, and one back to London, with another return from East Croydon to Brighton.