mlivingstone Posted February 5, 2014 Share Posted February 5, 2014 Now that is an interesting bridge/tunnel! Cheers Martin Link to post Share on other sites More sharing options...
ThePurplePrimer Posted February 5, 2014 Author Share Posted February 5, 2014 Hi big Jim That's an interesting setup but I can't quite fathom how it works ? If you have a spare minute could you explain it's operation please Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted February 5, 2014 RMweb Gold Share Posted February 5, 2014 Hi big Jim That's an interesting setup but I can't quite fathom how it works ? If you have a spare minute could you explain it's operation please It's called a wide-to-gauge trap point and the two switch rails move in opposite directions. When it is set to trap they stand as in Jim's photo and any wheels of an unauthorised move pass on the outside of the switch toes hopefully them being braked (to some extent) as teh switches widen out to normal gauge but itf it's a fast or heavy vehicle over-running the switches would probably cripple and bend over, or all over the place. The tw switch rail move in opposite direction against their appropriate stock rail thereby creating a normal gauge wheel path through the point. W-T-G switches are normally used where there is no safe run off to either side or where a run off to the side could possibly result in a collision and they're not at all common nowadays (they never were very common but there are far fewer about now that ever was the case in the past. Link to post Share on other sites More sharing options...
RMweb Gold big jim Posted February 5, 2014 RMweb Gold Share Posted February 5, 2014 Now that is an interesting bridge/tunnel! Cheers Martin it has been discussed in a previous incarnation of the forum Hi big Jim That's an interesting setup but I can't quite fathom how it works ? If you have a spare minute could you explain it's operation please the 2nd picture is facing the direction of travel, as you are looking at it the protecting signal is red and the catch point is protecting the line ahead so anything running towards it simply falls into the 4ft rather than be thrown off left or right when the signal is green the blades open out to complete the running rail as such, simple as that! EDIT: mikes explanation makes more sense than mine, never really thought about the blades acting as a brake as such, looking at the picture again i can see how it would work! Link to post Share on other sites More sharing options...
mlivingstone Posted February 7, 2014 Share Posted February 7, 2014 Gaah - FAIL I'm usually good at googling and searching but can't find the post you refer to on the interweb or old RMweb - I did login and and search Can you give us some pointers please? Cheers Martin Link to post Share on other sites More sharing options...
RMweb Gold big jim Posted February 7, 2014 RMweb Gold Share Posted February 7, 2014 i couldn't find it either, i am talking about 6-7 years back though! i think the discussion centred on quite how the hidden part of the girders was possibly set up Link to post Share on other sites More sharing options...
mlivingstone Posted February 9, 2014 Share Posted February 9, 2014 Oh OK, thanks for looking too Does anyone know the bridge name or number so I can search for a clearer picture please? I'm in NZ Cheers Martin Link to post Share on other sites More sharing options...
RMweb Gold big jim Posted February 9, 2014 RMweb Gold Share Posted February 9, 2014 its "picko No1 tunnel" also intestesting as its a curved tunnel you can see the daylight at the other end through! Link to post Share on other sites More sharing options...
RMweb Premium jamie92208 Posted February 9, 2014 RMweb Premium Share Posted February 9, 2014 its "picko No1 tunnel" also intestesting as its a curved tunnel you can see the daylight at the other end through! From those pictures you can clearly see the rivets that fix the end of the cross girders to the longitudinal girder. I would suspect that the pattern of cross girders then continue throughout the tunnel with jack arches of either brick or plate between them running across the tracks tat hold the ground cover above There would then I presume be a similar arrangement of girders at the far end depending on the geometry. Jamie Jamie Link to post Share on other sites More sharing options...
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