The program is technically very clear and obviously uses every byte of memory that the Model B and Electron can be persuaded to provide. Despite a 60 block load from tape, the program runs with a more than adequate graphical display - in a non-standard screen mode that provides five colours and varying degrees of resolution.
The display includes information on speed, fuel, etc and a graphical representation of the current incline. The steam engine remains in the centre with the setting of its various controls visible, while the scenery between London and Brighton is animated with reasonably realistic representation. Unfortunately, the techniques required to squeeze the program into memory have rendered it incompatible with the BBC Master.
I don't have any other steam engine train simulators in my collection, so the nearest comparison I can make is to flight simulators. Generally, it compares very favourably. I was particularly impressed by the options provided by Southern Belle. Instead of having to grapple with all controls at once, one can start by handling only the Regular, Cut Off and Vacuum Brake, while the computer controls the Whistle, Blower, Injector, Firedoor and Damper. As skill and confidence increase, you can opt to take any of these other controls under manual control. There are also a variety of options for journey types. For example, you can go for a simple straight London to Brighton run, or you can choose a slow stopping train where you have a very complex schedule to maintain. Some of the more difficult options will also provide unpredictable hazards for you to cope with.
Some simulations make very good computer games, regardless of your interest in the content. For example, my wife hates football but enjoys playing football management games. In the case of Southern Belle, whilst I think the implementation is probably as good as the limits of the machine allow, I feel it will nevertheless help to have a genuine interest in steam trains. The main problem is that since the program runs in real time, it really does take an hour to travel from London to Brighton and the play is pretty slow (although a save option is provided). For enthusiasts willing to invest the necessary time and patience, however, this program should provide a great deal of pleasure.