For those of you travelling by rail, you may occasionally notice a single person, or group of people at the end of a railway platform, avidly capturing the unfolding railway scene in every detail. Who are these people? They get abuse from the public and sometimes from rail staff, yet they religiously stick to their hobby with passion and enthusiasm. They get called names - "anoraks" being the favourite chant, due to the need to wear warm clothing while standing around in the depths of winter. Most members of the public see them as "train spotters", but there are many different kinds of rail enthusiasts, most of them males. I will attempt to explain them for you.

Rail enthusiasts (or railfans) do not simply take details of locomotives, simply to "tick them off" their list. It is far more complicated than that; it's the *element of control*. Think for a rail system as a giant chess set, or a jigsaw. The casual observer might be forgiven for thinking that engines and their trains (known as "rolling stock") can wander around a rail system at will. Not so. There are many different operating parameters that restrict this, for example:

• weight restrictions; an engine or its rolling stock can be too heavy for a particular rail route
• gauge restriction; the stock is designed for a specific line, and cannot be diverted to another line because it is too large in dimension and will strike, for example, over bridges or platform sides
• route knowledge; drivers are "passed out" on particular routes; they simply cannot take over another train if diverted, and they do not have clearance
• operating limitations; trains which are powered by overhead line equipment (OLE) cannot use lines without overhead wires

• personnel schedules; you want to maximise staff time and have them responsible for revenue-earning movements, rather than driving empty stock or travelling as passengers.

Staff, particularly those responsible for trains, must return to their home base after each day, or be accommodated overnight. A driver's schedule is known as a "roster" and the combination of engine plus rolling stock is known as a "link" (ie., the link of a chain).

Most rail systems work well when everything is going to plan. It is when thing begin to go wrong that it really interests the rail enthusiast. The rail authorities, for example, must make decisions what do they do when a particular line is blocked by a breakdown? How do they cope with the knock-on effect that will affect services later in the day? Is it worth terminating a particular train and returning it, simply to keep a service going? What happens in the lean-in to the Christmas break or any other period when the railway is closing for a day or two? How to they juggle the "links"?

Many rail enthusiasts had a model rail layout when they were young and, in some respects, the real thing is not dissimilar. The permutations can be endless, which is why some enthusiasts pay particular attention not only to the engine pulling the stock, but to the stock itself. They can tell you where the stock originated, what route it took and, probably, what engines hauled it during its journey. Nowadays, apart from mobile phones, one of the most useful tools for the enthusiast is a dictaphone, so they can call out the stock numbers as the train passes their viewing point, and not only the engine. It takes a certain amount of mental arithmetic to solve some of these conundrums.

Because of their deep knowledge of railways, enthusiasts can often be a good source of information. Sometimes station staff are given limited information on disruption, whereas the web of enthusiasts will have more detailed information from points far and wide. Additionally, the internet means that enthusiasts can share information quickly and efficiently. In these days of increased security, some rail authorities are asking enthusiasts to note anything unusual at a station and report it to the transport police. Rail authorities sometimes see enthusiasts as a nuisance, particularly if they are causing an obstruction or standing in prohibited areas (apart from the apparent nuisance value of someone looking over your shoulder).

It must be admitted that the vast majority of rail enthusiasts are men. There are female enthusiasts, and an increasing number participate in the preservation movement, which is great. It's a technical subject involving moving parts, something which attracts the male of the species. Many females don't like railways because they are perceived as being dirty (they often are). Men don't tend to notice such things.

Finally, many young boys dream of becoming rail drivers when they get older. some realise this dream but most do not. Rail spotting offers a way by which to continue the dream and the power of operating a railway. In these days of IT, more are turning to railway simulators for personal computers, particularly the popular Microsoft Train Simulator and another called Trainz. It is possible to operate an engine and pull rolling stock in the comfort of your own home!