Requirements Specification for the Fare Selling System for London Underground Page 1 of 17
file://K:\comp331\underground\LU.html 07/24/2001
Requirements Specification for the Fare Selling
System for London Underground[1]
Table of Contents
System Constraints
1. The Purpose of the System
2. The Client for the System
3. Users of the System
4. The Naming Conventions and Definitions
5. Relevant Facts
6. Project Constraints
7. Assumptions
Functional Requirements
8. The Scope of the System
9. Function and Data Requirements
Non-Functional Requirements
10. Look and Feel Requirements
11. Usability Requirements
12. Performance Requirements
13. Operational Requirements
14. Maintainability Requirements
15. Security Requirements
16. Political Requirements
17. Legal Requirements
Project Issues
18. Open Issues
19. Off-the-Shelf Solutions
20. New Problems
21. Tasks
22. Cutover
23. User Documentation
24. Waiting Room
Requirements Specification for the Fare Selling System for London Underground Page 2 of 17
file://K:\comp331\underground\LU.html 07/24/2001
g
1. The Purpose of the System
2. The Client of the System
The user problem or background to the project effort.
Selling tickets is currently done manually. According to traveller surveys, it takes too long, and is too
inconvenient. Staffing levels do not allow for full-time fare collection coverage at all stations.
Purpose London Underground Management want to encourage people to use their network, and want to
eliminate most of the fare evasion that happens as a result of difficulties with the current manual
approach to fare collection.
Goals of the system.
G1 To provide a way of selling tickets faster than at present.
Purpose To increase sales, increase customer satisfaction, reduce congestion, reduce fare evasion.
Fit
Criteria
The product shall sell tickets at least 15% faster than the existing system.
G2 To make buying a ticket more convenient for the traveller.
Purpose To increase customer satisfaction.
Fit
Criteria
Surveys taken after the installation of the new system must show a 30% increase in traveller
satisfaction.
Who is paying for the development, and who will ultimately own the delivered system?
London Underground Operations Department. Ms. Victoria Line (aka Dr Debbie Richards) has been named as
the person with ultimate responsibility for accepting the new system.
What is a successful solution worth to this client?
London Underground expects to gain £300,000 per day in extra revenue from the successful implementation
of a new system.
What happens if we don't solve this problem?
The client will resort to a contract system builder.
Requirements Specification for the Fare Selling System for London Underground Page 3 of 17
file://K:\comp331\underground\LU.html 07/24/2001
3. Users of the System
4. Naming Conventions and Definitions
This section gives definitions of terms, including acronyms, used in the project.
Please note that the following dictionary is not yet complete.
Fare Type
This is the kind of fare that can be bought. At the moment, the allowable fare types are Single, Return,
Weekly, Monthly, Annual or Day Rover.
Network Status
This is to show where problems exist in the rail network. For example, trains break down, signals fail,
and people sometimes fall under trains. Any of which can block the system.
Permit
The device, usually a ticket, given to the traveller in receipt of a fare payment. These may vary
according to Fare Type and Traveller Characteristics. For example, season tickets need to be more
robust and secure than single-trip tickets.
Station
The nodes of the rail network. Permits are bought only at stations. A journey starts and ends at stations.
Ticket
A machine printed, magnetically encoded entitlement to travel on the London Underground.
Traveller Characteristics
Some travellers are given discounts according to their categories. At present, the recognized categories
are Pensioner, Child, and Special Allowance. The latter covers London Underground employees and
the police.
Zone
All stations are in a conceptual geographic zone. Travel between different zones is charged differently.
All destinations in the same zone attract the same fare.
The users will be travellers on the London Underground rail network. They will be made up of:
z Commuters using the network every day. This category will make up 76% of the total traffic and must
be given priority.
z Tourists who may not speak or read English.
z Children. It is anticipated that they will be at least 7 years old.
z First time users.
z Blind people and people with impaired vision.
Part of the product (the travel permit) shall be indirectly used by ticket inspectors.
The product shall be operated by station staff.
User participation requirements.
Test panels of travellers will be made available for interviews and testing prototypes. These will be drawn
randomly.
Six London Underground station staff have been assigned to the project. They are available full time.
Requirements Specification for the Fare Selling System for London Underground Page 4 of 17
file://K:\comp331\underground\LU.html 07/24/2001
5. Relevant Facts
6. Project Constraints
7. Assumptions
External factors or predicted changes that have a bearing on the system but are not covered by other
sections.
It is anticipated that, from time to time, new fare structures will be introduced. These may cause the system to
be radically overhauled as allowance cannot be made for the, yet, unknown changes. It is possible that
different fares, for the same journey, will be charged at different times of the day, or according to the number
of people already using the rail network.
This section describes mandated constraints on the way the product must be produced.
C1 The product shall issue a permit/ticket.
Purpose The traveller must be able to prove that the fare has been paid.
Fit
Criteria
The completion of all ticket purchases shall result in the production of the correct travel
permit/ticket.
C2 The permit/ticket issued by the product shall be able to be read at all London Underground automated
ticket barriers. That is, the permits/tickets must be capable of correctly operating the barrier at the
departure station and the destination station.
C3 The fares charged are dependent on distance. Thus the system must recognize and correctly charge
for the traveller's destination. All destinations in the same zone will be charged the same fare.
C4 Permits/tickets must be transferable to buses. That is, they must be recognizable to inspectors and
conductors on the London bus system.
C5 The product must be available at all stations.
How long do the developers have to build the system?
C6 The product must be available for use at the end of the year. The Minister of Transport has promised
the House that it will be available by then.
A1 The developers are assuming that the ticket barriers will be as specified, and that they will be ready for
testing the Fare Selling System (FSS). The schedule for testing will be published separately.
Requirements Specification for the Fare Selling System for London Underground Page 5 of 17
file://K:\comp331\underground\LU.html 07/24/2001
8. The Scope of the System
Figure 8.1: The Context Diagram
Event Input Output Business Objects
1. Traveller wants to make a
journey.
Route and Price
Enquiry
Recommended Route
and Fare
Stations, Fares, Zones
2. Traveller buys permit/ticket. Permit/ticket
Purchase
Travel Permit/ticket
Charge
Fares, Stations, Zones,
Permit/ticket Sales
3. Fare management decide new
fares.
Travel Routes and
Prices
Permit/ticket Fares, Zones
4. Network management change
the network configuration.
Rail Network
Configuration
Stations
5. Time to reconcile fare
payments.
Payment
Reconciliation
Fares, Permit/ticket Sales
6. Time to analyse permit/ticket
sales.
Permit/ticket Sales
Analysis
Origin Station, Destination
Station, Permit/ticket Sales
7. Fare management change the
zone structure.
Zone Structure Zones, Stations
8. Network management advises
change of network status.
Rail Network Status Stations
Table 8.1: Event List
Requirements Specification for the Fare Selling System for London Underground Page 6 of 17
file://K:\comp331\underground\LU.html 07/24/2001
9. Functional and Data Requirements
Functional requirements.
R1 The product shall recognise valid fare types, traveller characteristics and destinations provided by the
traveller.
Purpose To avoid miscommunications with travellers.
Fit
Criteria
The product must reject any request that does not match the current fare structure and operational
destination stations.
R2 The product must advise if invalid fare types or destinations are requested.
Fit
Criteria
The traveller will be advised of all requests that do not match the current fare structure or the current
operational network.
R3 The traveller must supply the destination zone only.
Purpose To make the purchase of permits/tickets more flexible and fast.
Fit
Criteria
100% of 1000 tests using zone-only destinations will result in the correct permit/ticket being issued.
R4 The product shall check if the destination station is operational.
Purpose To avoid selling permits/tickets to destinations that cannot be reached.
Fit
Criteria
100% of the time the product verifies that the destination station is an operational station according to
the current rail network status.
R5 The product shall check that the destination station is valid.
Purpose London Underground does not wish to issue permits/tickets for stations that are not part of its
network.
Fit
Criteria
100% of the time the product verifies that the destination station is a valid station according to the
current rail network.
R6 The product shall inform the traveller if the destination station cannot currently be reached.
Purpose It will annoy travellers if they are able to purchase permits/tickets to destinations that cannot be
reached.
Fit
Criteria
100% of 1000 tests using non-operational stations result in the product informing that the station
cannot be reached.
Requirements Specification for the Fare Selling System for London Underground Page 7 of 17
file://K:\comp331\underground\LU.html 07/24/2001
R7 If the traveller supplies only a zone destination and there are problems in the zone, and it is possible
that the journey may not be completed or could be delayed, the product must inform that there are
problems and suggest that the traveller supply an exact destination.
Purpose It will annoy travellers if they are able to purchase permits/tickets to destinations that cannot be
reached.
Fit
Criteria
100% of 1000 tests involving stations in zones where problems exist, result in the product informing
of those problems.
R8 The product shall provide the quickest route to the destination station.
Purpose London Underground wants travellers to be in the network for the least possible time. London
Underground wants travellers to feel that the tube is the fastest way to travel around London.
Fit
Criteria
The route will always be the one with the least change and interchanges and where there are no
problems according to the rail network status at the time of the transaction.
R9 The product shall provide the cheapest fare for the traveller's fare type and destination.
Purpose Travellers shall believe that London Underground provides good value and is trustworthy.
Fit
Criteria
Every fare provided must be the cheapest allowable according to the current fare structure.
R10 The product shall inform the traveller of the suggested route and fare.
Purpose To facilitate the purchasing of permits/tickets.
R11 The product shall be able to cancel a transaction and return money at any time before the permit/ticket
is dispensed.
Purpose To allow the traveller to change his/her mind.
Fit
Criteria
A test panel of users shall be consistently able to abort transaction up to the moment before
committing to buy a permit/ticket.
R12 The product shall issue a permit/ticket when the fare has been paid.
Fit
Criteria
At least 98% of valid permit-buying transactions result in a permit/ticket being issued.
R13 The permit/ticket shall identify the journey for which it was bought and the fare type and traveller
characteristics.
Purpose To inform the traveller. To allow permit/ticket inspectors to verify that the traveller is making a legal
journey.
Requirements Specification for the Fare Selling System for London Underground Page 8 of 17
file://K:\comp331\underground\LU.html 07/24/2001
R14 The permit/ticket shall operate the ticket barriers both at the departure station and the destination
station. It shall work correctly in all stations in the destination zone.
Purpose The permit/ticket selling system must work with the ticket barriers.
Fit
Criteria
10,000 tickets to and from random stations will be generated. They must have a 99% success at
operating their legal barriers, and 99% failure at operating illegal barriers.
R15. The permit/ticket must show the journey details in English.
Purpose The ticket inspectors must be able to read the permits/tickets.
Fit
Criteria
A test panel of inspectors are able to read 1000 randomly-produced permits/tickets.
R16 The product shall accept payment for the fare.
Fit
Criteria
The payment reconciliation reports for the first six months of operation should reveal that all
dispensed permits/tickets were paid for.
R17 The product shall accept all coins of 5p and above. It also shall accept 5, 10 and 20 pound notes.
Purpose These denominations make it easier for the traveller to buy a ticket and easier for the product to both
recognize and reconcile payments.
Fit
Criteria
1000 tests using a random assortment of allowable coin and notes must yield 98% successful sales.
R18 The product shall accept multiple payment methods. Credit cards and cheques may be used for
transactions above £10.
Purpose Traveller convenience.
Fit
Criteria
50 tests using random payment methods must all result in a permit/ticket being issued.
R19 The product shall detect invalid currency.
Purpose To ensure London Underground receives the value for the fare, to make it easier to reconcile
payments, to make the product easier to construct.
Fit
Criteria
The product conforms to the appropriate banking standards.
R20 The product shall inform the traveller of the amount required, and the amount remaining to be paid.
Purpose To facilitate the transaction.
Fit
Criteria
The fare told to the traveller shall always conform to current fare structure. The amount remaining is
always the fare less the amount already given by the traveller
Requirements Specification for the Fare Selling System for London Underground Page 9 of 17
file://K:\comp331\underground\LU.html 07/24/2001
Criteria always the fare less the amount already given by the traveller.
R21 The product shall only accept Sterling currency.
Fit
Criteria
98% of 10,000 random foreign coins and notes are rejected.
R22 The product shall record a sale for each issue of a permit/ticket.
Purpose To prevent fraud.
Fit
Criteria
The payment reconciliation shall exactly match the number of fares sold.
R23 The product shall issue change.
Purpose If payment received is greater than payment required, the product must refund the difference.
Fit
Criteria
1000 tests using cash will be run. In all cases where change is due, it must be dispensed.
R24 The product shall inform the traveller that change is being dispensed.
Purpose It should be difficult for the traveller to not realise he/she is due change, and/or leave before the
change is fully dispensed.
Fit
Criteria
The tests shall be as for R23. The product must inform that it is dispensing change in all tests.
R25 The product shall dispense the correct change.
Fit
Criteria
In 2000 tests with random payments tendered the system always provides the correct change.
R26 The product shall cease to operate if change is unavailable. In this case it will inform intending
travellers and alert station staff.
Purpose It is important to always dispense the correct change.
Fit
Criteria
The product shall cease to be available if the amount of its available change is less than the difference
between the largest payment denomination and the cheapest fare.
R27 The traveller shall be able to buy more than one permit/ticket in a single transaction.
Purpose Family groups need only one person to buy all their tickets.
Fit
Criteria
100 tests shall be run with attempts to buy multiple permits/tickets. All shall be successful.
Requirements Specification for the Fare Selling System for London Underground Page 10 of 17
file://K:\comp331\underground\LU.html 07/24/2001
R28 The product shall be updatable with the new fare structures.
Purpose From time to time the fares are changed. The product must always sell permits/tickets at the correct
fare.
Fit
Criteria
All permits/tickets are sold at the correct fare.
R29 The product shall update the stored fare structure.
Fit
Criteria
The fare structure stored shall be compatible with the fare structure provided by LU Management.
R30 The product shall be updatable with the new network configuration.
Purpose It must be remembered by the product.
Fit
Criteria
The network configuration must be retrieved, and must conform to the one published by Network
Management.
R31 The product shall check that a new network configuration does not cause any conflicts with any other
requirements.
Fit
Criteria
Within the first three months of testing and operation, there shall be no reports of malfunction due to
configuration problems.
R32 The product shall allocate every station to a zone. Each station, no matter how many lines enter that
station, must belong to only one zone.
Purpose Fares are dependent on the zone of the destination station.
Fit
Criteria
Each line in the rail network will be examined. There shall be no inconsistencies between zones for
any station. All stations must be associated with a zone.
R33 Stations that have been taken out of service shall remain in the product's stored data, but flagged as
"out of service."
Purpose Permits/tickets must not be sold to these stations, but the product must be able to inform travellers
that these stations are not valid destinations.
Fit
Criteria
Test stations will be flagged as out of service. Any attempt to buy a permit/ticket to one of those
stations must be unsuccessful.
R34 The product shall, either on demand, or at predetermined times, produce a report known as the
Payment Reconciliation.
Purpose London Underground Accounting need to know the amount of money collected by the product.
Fit The report content must agree with that specified by the Accounting Office.
Requirements Specification for the Fare Selling System for London Underground Page 11 of 17
file://K:\comp331\underground\LU.html 07/24/2001
Criteria
R35 The Payment Reconciliation shall show all moneys collected by the product, and all fares sold by the
product. These collections shall be shown for each collection point (ticket seller, machine, etc.) and
for station as a whole.
Purpose The auditors need this requirement.
Fit
Criteria
As for R34
R36 The Payment Reconciliation shall highlight all exceptions. That is, where the payments and the fare
collections do not match.
Purpose The auditors need this requirement.
Fit
Criteria
As for R34
R37 The product shall, either on demand, or at predetermined times, produce a report known as the Permit
Sales Analysis.
Purpose Both Network management and Fare Management need to know the volume of fares being collected.
Fit
Criteria
Mr. Brent Cross of the Fare Management Office will approve the report.
R38 The Permit Sales Analysis shall show the numbers of travellers who have bought permits/tickets.
These shall be shown in quarter-hour increments for the station as a whole.
Fit
Criteria
As for R37
R39 The product shall receive the new zone structure.
Purpose The product must remember the zone structure.
Fit
Criteria
The zone structure must be retrievable and must conform to the structure published by Network
Management.
R40 The product shall check that the new structure does not cause any conflicts with any other
requirements.
Fit
Criteria
Within the first three months of testing and operation, there shall be no reports of malfunction due to
the network structure.
R41 The product shall allocate every station to its new zone. Each station, no matter how many lines enter
that station, must belong to only one zone.
Purpose As for R32
Requirements Specification for the Fare Selling System for London Underground Page 12 of 17
file://K:\comp331\underground\LU.html 07/24/2001
10. Look and Feel Requirements
11. Usability Requirements
Fit
Criteria
As for R32
R42 The product shall be updatable with the new rail network status.
Purpose It has to be remembered.
Fit
Criteria
The network status must be retrievable, and must conform to the one published by Network
Management.
R43 The product shall update its knowledge of the rail network according to the new status. Stations that
are temporarily out of service must be shown as such. The product must know if an operational
station cannot currently be reached because of nearby problems.
Purpose The product must not sell permits/tickets to destinations that cannot be reached.
Fit
Criteria
Random network status updates will be recorded. 100% of 1000 attempts to buy a permit/ticket to
unreachable station must fail.
R44 The parts of the product exposed to the public must use the corporate colours.
Purpose Consumer identification.
Fit Criteria The London Underground logo shall occupy 15% of exposed surface area. The line name
and colour of the origin station shall occupy 20% of surface area.
Supporting Material Supporting Materials Marketing survey of passengers 1996.
R45 The product must be easy to use. It must use terminology that is already established, and
shall appear to be familiar to London travellers.
Purpose London Underground desires an easy acceptance of the new system.
Fit Criteria A test panel of first-time users will be asked to use prototypes of the product. 80% should
hesitate no more than 10 seconds before starting to use the product. The number of people
who refuse to use the product should be less than 10%.
R46 The traveller shall be able to use the product without any training.
Purpose Training travellers to use the product is too expensiv and impractical.
Fit 90% of a panel of 1000 first time users are able to purchase a permit/ticket within 45 seconds.
Requirements Specification for the Fare Selling System for London Underground Page 13 of 17
file://K:\comp331\underground\LU.html 07/24/2001
12. Performance Requirements
Criteria
p pp
R47 The product shall be easy to use.
Purpose To speed up the process and make it more attractive to potential travellers.
Fit
Criteria
The number of incorrectly bought permits/tickets shall not exceed 500 per day for the entire network.
This will be measured by the number of permits/tickets returned to the permit/ticket sellers.
R48 The permit/ticket shall be able to be carried conveniently, shall be as difficult as possible to lose.
Fit
Criteria
There must be a 10% reduction in the number of reported lost permits/tickets.
R49 The updates will be done by station staff.
Purpose To avoid hiring new staff.
Fit
Criteria
95% of a test panel must be able to make successful updates within 30 minutes.
R50 Travellers shall be able to understand their permits/tickets.
Fit
Criteria
The Human Communication Institute at Macquarie University (ie Dr Debbie Richards) will approve
the design and content of the permits.
R51 Ticket inspectors must be able to read permits/tickets.
Purpose They must know if the current trip is legal.
Fit
Criteria
As for R50
Defines constraints that affect the performance of the product.
R51 The product shall be available from 30 minutes before the first train of the day and until
the time for the last train to leave the given station.
Purpose Availability of the FSS is fundamental to the objectives of the new development.
Fit Criteria Six months of testing result in a 98% availability during the specified hours.
R52 The product shall issue a travel permit/ticket within 1 second of receiving travel details
and correct payment.
Requirements Specification for the Fare Selling System for London Underground Page 14 of 17
file://K:\comp331\underground\LU.html 07/24/2001
13. Operational Requirements
14. Maintainability Requirements
Purpose To make travellers believe that the product is working, and is efficient.
Fit Criteria 95% of 1000 valid test transactions result in a permit/ticket within one second.
R53 The traveller shall be able to purchase a permit/ticket quickly.
Purpose To speed up the sale of permits/tickets.
Fit Criteria 95% of a test panel of "experienced" travellers shall be able to purchase a permit/ticket
within 15 seconds of encountering the system.
Supporting Material London Underground Passenger traffic survey January, 1997.
R54 The product shall in no way be dangerous for the travelling public to use.
Fit Criteria The product must conform to the British Safety Council Standards for equipment
accessible to the public.
Expected physical environment.
R55 The product shall be used in noisy, windy, station forecourts by people who will often only have one
hand free.
Fit
Criteria
London Underground shall select 20 stations, that in their opinion, are the best and worst in the rail
network Test panels of travellers shall be 90% successful when buying permits/tickets in these
stations.
How easy must it be to maintain this product?
R56 New destinations will be added to the product at any time.
Purpose The product must keep up-to-date information on the rail network.
Fit
Criteria
For any destination being added, the product shall be unavailable for no more than 5seconds.
R57 Updates of network status and zones structures must take place without any disrupting the selling of
permit.
Fit The maximum inoperable time shall be no more than five minutes.
Requirements Specification for the Fare Selling System for London Underground Page 15 of 17
file://K:\comp331\underground\LU.html 07/24/2001
15. Security Requirements
Criteria
R58 Changes to fares will take place after close down of the rail network.
Fit
Criteria
The updates must be completed before the network opens the next day.
R59 The money received shall be secure from theft.
Fit
Criteria
The Metropolitan Police Crime Prevention office shall certify the product.
R60 Change shall be dispensed securely. That is, it must be very difficult for anyone other than the permit
buyer to get the change.
Purpose Surveys have shown that travellers are concerned that their transactions are secure and private.
Fit
Criteria
90% of a test panel of random travellers shall report they feel their transaction is secure.
R61 The product shall be difficult to defraud.
Purpose To protect London Underground's profits.
Fit
Criteria
The auditors shall certify the product.
R62 The product shall protect itself against malicious damage.
Purpose The product will be accessible in station forecourts. times it will be unattended. It will often contain a
considerable amount of money. It must be kept operational for the convenience of travellers.
Fit
Criteria
The Metropolitan Police Crime Prevention office shall certify the product.
R63 All information held by the product shall be confidential, and shall not be available to other products
or people. This requirement accepts the product's required reporting.
Purpose This is required by law.
Fit
Criteria
The auditors shall certify the product.
R64 Only Fare Management may change the fare structure and the zones.
Purpose To prevent unauthorized tampering.
Fit Persons other than a thori ed Fare Management personnel are not able to change the fares nor the
Requirements Specification for the Fare Selling System for London Underground Page 16 of 17
file://K:\comp331\underground\LU.html 07/24/2001
16. Political Requirements
17. Legal Requirements.
19. Off-the-Shelf Solutions
Fit
Criteria
Persons, other than authorized Fare Management personnel, are not able to change the fares nor the
zones.
R65 The product must provide an adequate audit trail.
Purpose To prevent fraud. To comply with the law.
Fit
Criteria
London Underground's auditors certify that the audit trail is complete and correct.
Are there any special factors about the product that would make itunacceptable for some political
reason?
R66 The product shall not be seen to discriminate against any group.
Purpose London Underground is a Government funded organization and must accommodate all possible
types of people.
Fit
Criteria
95% of a represented test panel do not feel discriminated against by using the product and 50% of
any group are not offended.
R67 The product shall obey all aspects of the London Transportation Law of 1995.
Purpose London Underground must obey all laws relating to the carriage of passengers.
Fit
Criteria
The London Underground legal department will consider that the product does not contravene any
relevant laws.
R68 The product shall comply with relevant European directives.
Purpose The Government is bound to uphold all relevant European directives
Fit
Criteria
The London Underground legal department will consider that the product complies with the
appropriate European directives.
Is there a ready-made system that could be bought?
There are no existing ready-made products that will work in London Underground's system. The
DuPont & Mercier product currently used in the Paris Metro was the closest match to the operating
conditions, but hardware constraints make it impractical.
Requirements Specification for the Fare Selling System for London Underground Page 17 of 17
file://K:\comp331\underground\LU.html 07/24/2001
[1] This document is a slightly modified version of one available from http:www.cuc.ucc.ie/CS3000/notes/LU.html, who are owners of
the copyright of the original document. For project management and testing material see
http:www.cuc.ucc.ie/CS3000/notes/Methodology.html
22. Cutover
23. User Documentation
24. Waiting Room
What special requirements do we have to get the existing data, and procedures to work for the new
system?
R69 Existing long-term permits/tickets must be honoured by the new product.
The plan for building the user documentation.
R70 The following user documentation shall be produced:
z Product description for Network Management.
z Product description for Fare Management.
z Product description for Accounting.
z Operators' manuals for station staff.
A publicity campaign will be run to inform travellers of the new product. This is to be handled by the
London Underground PR Unit.
Requirements that will not be part of the planned next release, but will be considered for future
releases.
R71 Camets. A "book" of 10 tickets for travel in zone shall be sold at a special price.
R72 Special events and promotions. For example, tickets to Wembley on FA Cup Final Day would be
specially printed as souvenirs.
R73 Commercial firms may "sponsor" a station. For example, permits/tickets bought with a destination of
Knightsbridge would carry an advertisement for Harrods.