What does this inscription on a railroad rail mean? south wk 5 vii 901?

Question

What does this inscription on a railroad rail mean? south wk 5 vii 901?

Answer 1

we have markings on rail in the States that give the manufacturer, the date and the size of the rail in pounds per yard.

I am guessing those marks are similar, just coded differently  so that I can't decipher them.

There are people that collect lengths of rail that have these inscritpions on them, expecially the very old ones.

Answer 2

Looks like a UK marking to me.

In the US, you'll see a number of "hash marks" on the rail, followed by a number.  This is used to indicate when the rail was made.

This is important information, as it is a permanent date marking for telling not only the age of the rail, but narrowing the search if rail proves to be not "up to snuff," for whatever reason, so the batch can be identified.

It is not really needed any more, account the computer age allows for much more info to be permanently stored.

Likewise, "date nails" were employed for years, driven into cross ties at certain intervals, recording the date the ties were laid.