I NOTE with interest you report disruption caused by night-time freight trains ("Noisy night-time trains found to breach health guidelines", The Herald, November 18).

Could it be that the cause of the noise and vibration is the fact that the ground between Stirling and Kincardine is a honeycomb of old mine workings? This has led to an ongoing problem track-wise since the route was fully re-opened, with Network Rail undertaking track renewal work in a bid to rectify this.

I can recall a (then) new railway yard opening near Alloa in the 1960s whereby the sidings resembled a switchback due to subsidence. The present-day coal trains cannot be re-routed over the Forth Bridge as was done previously due to their having a higher overall weight.

Do the protestors envisage the use of road transport in lieu? I hardly think so.

John Macnab,

175 Grahamsdyke Street, Laurieston, Falkirk.