On most railways where there are two tracks, historically the space between the running rails of each track was known as the "four-foot", as the standard gauge is 4' 8 1/2 ", and the space between the outside rails of each track was known as the "six-foot" (it was actually rather more, but that isn't of particular relevance here).

At all events, the "six-foot" is the same as the "wide way", and the UIC (International Railway Organisation) dictionary gives this as the translation.

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Note added at 13 hrs (2006-10-03 11:54:29 GMT)
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Not sure if that should be "the INNER rails of each track"; at all events, it's the spacing between the tracks... and of course with today's higher and higher speeds, new railway lines are being laid further and further apart with increasing speed than the old "six-foot", to reduce passing trains' air-pressure impact on each other.