I am unsure of the English translation of many of the terms, but I think I can give you enough to get you on the right track, no pun intended.

sidospår = side track (or possibly spur track)
sidotågspår = siding
skyddsväxlar = trap points (in the UK)
som medger det = "det" refers to "växling" (not clear, I think)
det kan ställas tågvägar = routes can be set
huvudtågspåret = the main line (or just "the line")


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Note added at 45 mins (2004-04-21 09:17:11 GMT)
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I am uncertain of the exact meaning of \"växlingsområde,\" which is a crucial term here, and I have no idea what it\'s called in English.