The tram lines are a very pale yellow cream.
A friend of mine now passed Sid (BVWS Member also known as Southampton Sid) worked for Philips after the war and when I complained about repainting the tram lines he told me there were just a couple of girls painting them freehand.
Sid was the first member of the BVWS to befriend me when I rocked up to Harpy all those years ago a real gent
The nearest I could find 20 years ago was a Dulux pale cream emulsion goes on thick like the original.
I always had to clean up afterward with a damp cloth
Got an acceptable result but not as even as the original.
Cheers
Mike T