Trying to identify the font used for the old-stype London Underground / Tube station signs. Not sure if it's a common font or not.

Thank you!!

Some other examples:
http://www.firedearth.com/media/catalog/product/cache/1/image/375x/9df78eab33525d08d6e5fb8d27136e95/u/s/uszoo.png
http://www.firedearth.com/media/catalog/product/cache/1/image/375x/9df78eab33525d08d6e5fb8d27136e95/u/s/uspiccadilly.png
http://www.firedearth.com/media/catalog/product/cache/1/image/375x/9df78eab33525d08d6e5fb8d27136e95/u/s/usgap.png

All your samples show different typefaces.

Hmm... OK, then let's just focus on the main Way Out font please. And thank you.