Gatwick Express 387 220 & 227 Seaford 3 2 2024

These trains are from the Bombadier Electrostar range. They are general purpose electric multiple unit passenger trains used that have been used extensively on the three-rail system, south of London. The term Express was used to differentate these trains from Gatwick Airport into Victoria station, in central London from the others. Initially they ran direct between the two stations without stopping, except for one stop on some services at East Croydon, a major junction in south London. They now run on down to Brighton on the south coast. There have been several different models of trains used since its inception, the 387 ElectroStars being the most recent. The route is only 23 miles / 38 km long and runs through busy commuter lines, so is not a really high speed service. Other trains on the route stop at many more stations.
With lower demand on the Gatwick route, due to additional connections being available, including with the new East to West London Elizabeth Line, the red trains are being used elsewhere, notably along the south coast, as seen here.