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Gauging and Clearances

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Vivek Vilay

04 November 2015, 6:35am


I am looking for more info about gauging and clearances, specifically, I find that it is interesting the way in which a vehicle has been assessed as far too tight to traverse by lineside structures, is then physically allowed to run and actually ends up passing clear of the structures without touching them, with repaeatibility.

There is an article in Journal 09/15 which discusses this problem but my question is,

what parameters are added on and how are these parameters assessed, post trial runs when the vehicle is clear or even when it ends up striking a lineside structure.

Matthew Ansell

12 November 2015, 12:19pm

Hi Vivek,

I believe the profiles of vehicals are measured under four seperate parameters, tare and crush deflated and inflated to give the worst case senario for each profile. There is also the ageing factor dependant on track fixity which from memory can be applied up to 3 consecutive years up to 25mm per time so a maximum additional measurement of 75mm after 3 years can be added to the potential kinematic envelope. For more information the techs at laser rail should be a good port of call.

Hope this helps



Vivek Vilay

18 January 2016, 2:07pm

Thanks Matthew

very interesting. It becomes a diffuicult job for railways with very tight clearances ~50mm range as a couple of years of ageing factors applied would render the structure foul.

I hear the ageing factors do not take into consideration the traffic volume/ tonnage and type of curvature, which would have a huge impact. maybe a higher reduction value for heavily trafficed routes on a tight curve verses a lightly trafficed route on a straight...

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