While I agree with R J Ardern's letter regarding the replacement of the rolling stock on inter-city rail routes in Scotland (April 21), I fear your correspondent is whistling in the dark with calls for increased capacity on single-line tracks in the Highlands. These calls have been ongoing since 1951 when the Scottish Council Development & Industry produced a report on Highland transport costs which called for the same thing.

The same calls were repeated in 2005 in the Smart, Successful Highlands and Islands report. As yet, neither has been acted on. The fact is, since the Second World War successive governments have been unwilling sufficiently to improve transport links in what is one of Scotland's primary tourist earners.

If Scotland is to move forward economically then an integrated transport system is paramount, not just in the Highlands, but over the whole country. The replacement of rolling stock is only one of many requirements for a transport infrastructure for a forward-moving, dynamic economy. Relying on Westminster to implement these measures has shown to be futile.

Niall G MacKenzie, London.