Trainspotters can be found at stations, at engine depots, and alongside the rails themselves, noting down train and engine serial numbers. The point of this seemingly pointless hobby is to spot and record the serial numbers of all engines (and, for the true enthusiast, carriages as well) currently in use. The only difference is that trainspotters tend to stay in one place, whereas wardrivers are in constant motion, trying to cover as big an area as possible.”]
Source: https://securelist.com/war-driving-and-trainspotting/30172/