As Richard has said, in England if there is a very long platform (such as at Gloucester), it is split into a number of platforms: here an edited quote from Google:
"Gloucester Station has the longest platform in the UK, as mentioned in the Guiness Book of World Records. It is about a mile long! However, each platform is split into 2 or 3 platform numbers." http://www.myledbury.co.uk/photo/railweek/rai...
So the 11:43 to Cardiff arriving at platform 1 may well be on the same track as platform 2, but not the same platform (although physically speaking, it is on the same continuous piece of concrete, just as a "Gleis" may be theoretically split into several parts on a single "Bahnsteig", but there is of course no break in the tracks).
Wolfman: your comment >Im Hauptbahnhof von Essen gibt es einen Bahnsteig für die Gleise 7, 8, 9 und 10. Das kann man nicht als "platform 7, 8, 9 and 10" bezeichnen."< is entirely wrong.
>Mich stört die 1zu1-Übersetzung von "platform" und "Gleis".<
I actually agree with the principle you are defending. But no-one here has ever said, and no-one in their right minds would insist, that those two words cover precisely the same meaning. But in the context of stations, they correspond to each other perfectly.
If you have to distinguish between the track and the platform ("he fell off the platform onto the track"), of course you wouldn't use the word "Gleis" twice. But in the context given, the only possible translation for "Gleis" is "platform".