1 Introduction

“My bus is coming!”

We have probably all said this at some point in our lives. But what exactly do we mean by it? Is our bus really a physical vehicle? In such cases, the passenger is not usually thinking about a very specific vehicle. From the passenger’s point of view, it is important that the bus or tram arrives at the stop at the correct time and travels in the right direction.

Bus – Trip

However, if our passenger happens to be a computer scientist and is particular about terms, then he might say: “My trip is coming!” This sounds quite strange, doesn’t it? Granted, but what happens when we are at the airport?

Aeroplane – Flight

“Our flight is delayed. I heard that the plane hasn’t even landed yet.”

Everyday language makes a clear distinction between “the plane” and “our flight”. At this point, it is still a foreign machine – it only becomes “our plane” when it begins ourflight. We have booked a flight and not a specific aeroplane.

Trip = route, direction, time/place

But let’s return to earth. We might have noticed that our bus is often very full in the morning. Actually, we should formulate this as follows: Thetrip onroute 12, which, according to the timetable, is supposed to depart at6:50 from thestop Cherrytree Road, travelling in thedirection to Exhibition Centre, is close to full capacity. Somewhat wooden, but correct. By specifying the route number and direction of travel along with a stop and departure time at this stop, we are able to identify the trip.1

Vehicle type

One day we are standing at the stop 10 minutes earlier. Even more people are waiting than usual. We have already mentally prepared ourselves for a standing place, but, when a vehicle arrives at 6:43, we see that it is a large articulated bus. The transport company clearly deploys a variety ofvehicle types on this route in order to adjust the transport capacity to the demand.

Vehicle

One morning, after exiting the vehicle, we realise that we have left our umbrella in the bus. As we can see the stop from our office window, we keep glancing at it and wondering if thevehicle with our umbrella might drive by again. According to the timetable, the entire runtime from the initial stop to the final stop takes 45 minutes. This means that “our” vehicle should actually come back here in 90 minutes. Or perhaps even earlier, but in the opposite direction?

Vehicle workings, break times, driver changeover, vehicle swap

One colleague thinks that we should take our time, because a break for the driver is always scheduled at the final stop. Another colleague argues that the driver is sometimes changed at the final stop. Does this mean that the break for the vehicle consequently does not take place? Eventually, someone declares that he has never seen an articulated bus after 9am.

Disruptions

“Recently there was a traffic jam and the driver asked us to exit and wait for the next vehicle. Then our vehicle turned around and drove straight back.” After much heartening encouragement from our colleagues, we decide to ask the transport company directly about our umbrella in the afternoon.

Dispatch

The friendly employee on the phone tells us: “A driver on route 12 found a green checked umbrella today at the final stop at Exhibition Centre. He told us about it via the on-board computer in his bus. The vehicle is still being operated, but the driver has already finished his shift. The driver who is driving the bus now will take the umbrella to the depot tonight. We will make sure that you are handed your umbrella tomorrow morning when you board the bus at Cherrytree Road. It will be a different vehicle and a different driver – but that is nothing for you to worry about! Just give the driver the code word when you board the bus: “Top class service.”

Thus, we have reached the – perhaps slightly fanciful – end of our short introduction. We have encountered a number of aspects that will be described in more detail later on in the book: stops, links, travel paths, routes, vehicles, vehicle types, trips, drivers, duties, break rules, dispatch managers – in short: the entire, astonishing diversity of public transport (PT).

1.1 IT systems in PT are complicated!

In terms of subject matter, IT systems in public transport are astoundingly complicated, in addition to being very sophisticated from a technical point of view:

Buses with electronics

• The bus in public transport can do more than just drive: it knows its timetable, announces the stations, reports to the traffic lights and continually informs its control centre of its current position. Aside from that, it takes care of selling tickets and calculating revenues – as well as displaying possible transfer connections, both based on the timetable and in “real time”.

  Algorithms

• Designing timetables is a very demanding job. A complicated network of vehicle movements and driving duties needs to be drafted in order to provide cost-effective transport services. The optimisation of timetables and duty schedules is still a current field of research at universities; from a certain size of transport company upwards, the deployment of scientific procedures2 is absolutely essential.

  Complex databases

• IT systems in transport companies are based on databases with hundred of tables; you come into contact with complicated mechanisms for historisation, versioning of timetables, multi-tenant capability and numerous methods for optimising performance.

  Real graphics

• The user interface not only contains the usual “graphical” screen forms, but also realgraphical user interfaces, i. e. maps and schematic route plans, track outlines, etc.

  Special hardware

• You encou