All London Underground lines have cushioned, upholstered seats. You can even tell which line you’re on because each line has a unique fabric pattern known as a “moquette”:

https://londonist.com/london/transport/all-the-tube-moquette...

(The fabric does wear out eventually, but it seems relatively cheap and easy to replace. It’s rare to see a dirty or overly worn out seat)

Commuter trains into London often have carpeted floors, too, depending on the operator and type of train. It does make for a quieter, more civilised experience!