Permit to Travel Ticket Issuing System (PERTIS) Machines (commonly referred to as ‘Permit to Travel Machines’) are a type of ticking machine introduced into the British Railways networks from 1988^[1], in order to tackle the issue of fare evasion without the need for costly Ticket Vending Machines (TVM).

PERTIS Machines are usually located within station where a Penalty Fare Scheme operates and there are no other cash accepting self-service machines available. Passengers insert as much coinage as they can (up to the value of the fare for the journey) into the machine. They press a green button and a permit is printed. The permit is then valid for 2 hours in which the passenger has to exchange the permit for a full ticket. This is typically a guard, another ticket office or excess booth.^[2][3]

PERTIS Machines only accept coins in the 5p, 10p, 20p, 50p, £1 and £2 dominations. However due to a change in mintage of the 5p and 10p coins in 2010, The AS88/89 PERTIS Machines will not accept the new coinage^[4].

In March 2017 a new £1 coin will be launched^[5]. Validators for the new £1 have been made available by metric group^[6]. London Midland has stated they will be getting their validators upgraded to accept the new £1 coin^[7].

Autoslot 8

The first PERTIS Machine was based on the AS-8. These were the first PERTIS Machines which were trialed on what is now the c2c line between Fenchurch Street and Shoeburyness. These were wall mounted machines. Unlike the AS88/89, the money is stored within the main part of the machine rather than the pedestal^[10].

The maximum amount of money these machines accept is £20^[11].

Autoslot 88/89

The second type of PERTIS Machine was based on the AS88 and AS89 machines. These are by far the most common type of PERTIS Machine with over 700 being manufactured^[10]. The autoslot PERTIS machines use dot matrix printing to print onto the tickets^[12].

The autoslot machines will number each ticket printed sequentially from 000-999. The ticket will also contain the name of the station, the amount paid, the date/time and a machine reference number (typically 01, 001, 01A, 02 etc.). They print onto a cardboard ticket stock^[13].

Aura

The third and latest type of PERTIS Machine is based on the Metric Aura. These have only ever been installed on South West Trains^[14] and East Midlands Trains^[15][16] Networks, However East Midlands Trains are in the process of removing all of their PERTIS Machines^[17]. South West Trains use Aura MK1s whereas East Midlands Trains used the Aura Phase 2. However this is not strictly kept to where parts of machines have been replaced due to vandalism^[18]. It is notable that these PERTIS Machines have been supplied in black/grey rather than red. The maximum amount of money these machines can take is £30^[19]. These machines use thermal printing technology to print onto the tickets^[20][21].

Like the autoslots these tickets will have the station name, machine reference number, date/time and amount paid printed onto them. However these machines will print a ticket number of up to 5 digits, with a security barcode^[22].