Watch on Soap2day. The Metropolitan main line is now the exclusive domain of S8 stock trains introduced between 2010 and 2012. The iconic “A” stock trains plied the route for over 50 years, firstly in unpainted aluminium finish and later in refurbished blue, red and white Underground colours. Filmed in 1995, here you can see both incarnations of the A stock at work – a tastefully refurbished train running on the main line, with unpainted stock (with the inevitable graffiti) running on the branches.