Wellcome Lancer. I'd go with all that is said above.
LGB's ubiquitous code 332 rail/45 mm gauge track system has a number of "straight fit" compatibles - Bachmann (brass) USA Trains, Aristocraft, Accucraft, Piko, Trainline, etc'. All sold in the UK and are mostly available new and 2nd hand. There may be some differences in sleeper spacing appearance and spacing between them though. There are some specialist suppliers that use LGB's rail as a basis for some useful track items in configurations the mainstream suppliers don't, like Garden Railway Specialist's Double Slips. Be aware there is another maker of a Code 332 rail based system, Tenmille, while it is compatible with LGB types it require special adaptors to join.
The beauty of LGB type is, apart from its robustness, is that just about any bit of track geometry can be obtained off the shelf to meet your operational heart's desire. Max