In my work as an MP, one of the things that gives me the most pleasure is my role as the president of the Friends of the Far North Line. This is because, when I think about it, the railway north from Inverness has always played a large role in my life.

The wee boy running across the field to wave to the engine driver and fireman as the north train is pulled out of Tain station? That was me.

I was brought up beside the railway line. The length of my childhood day was punctuated by the passing of passenger and goods trains in both directions. Later as a teenager, I used to go down to Tain station and talk to Malcolm 'Duckie' Munro who ran the station.

With my first camera, I took pictures of the trucks in Tain sidings and the first green or blue and yellow diesel engines that started to replace the black steam engines when I was about six. When I shut my eyes at night I think back, I am that wee boy again.

Our forefathers, way back in the 19th century, were very far-sighted when they built the railway lines that helped make the UK the world's first industrial giant. Many legacies of the past are merely artefacts of historical interest, such as canals, but this is not the case with the railways.

If we are to be serious about global warming as a country, then using one railway engine - preferably electric - pulling many coaches or wagons, instead of having all those cars and lorries belching out fumes on our roads makes enormous sense.

The Friends of the Far North Line has a membership consisting of people like me: railway enthusiasts. They are something of a ginger group that gives time and thought to how the Far North Line can be improved and made better use of.

Most recently, they made the point that the most welcome announcement of the Cromarty Firth Green Freeport can, and should, lead to more goods - and people too - being transported by rail to Invergordon.

Of course, this was the case during both the First and Second World Wars when the Cromarty Firth was one of the homes of the UK's naval might. There used to be a junction in Invergordon leading to the waterside, but that was torn up when so much of our rail infrastructure was shortsightedly removed by successive UK governments.

But that was then, and this is now. I believe that the old plans should be dusted off and that we should think quite strongly about reinstating this method of getting goods and people right to where they can be embarked on ships for travel and export.

But it is possibly an even bigger deal than simply the Freeport, it is a fact that as the polar ice cap retreats owing to global warming, cargo ships will increasingly be able to sail all year round what we call the North East Passage to markets in the Far East such as Japan. It is a far shorter route than sailing the other way either through the Suez Canal or around the bottom of Africa.

This could mean that seaborne freight activity might increase both out of Caithness and indeed the old naval anchorage in Orkney's Scapa Flow. Of course, I am crystal-ball gazing, but global warming is a reality, and experts are talking about this route.

We might be very wise to at least plan the necessary rail infrastructure that would help this happen.

But you might say: "We already have a railway line to Caithness". But if the line north of Inverness is used more frequently for passenger and goods traffic, then the trains have to get past each other - and when the line was first built in the 19th century, this was done by means of what was known as passing loops, i.e. stretches of double track where a train could pull up while one going in the opposite direction passed it.

Yes, I am still the wee boy waving at the railway engine, but one thing I do have is the power as an MP to write to the Scottish Government and the UK government to urge them to think about these matters. As I lay my pen down now, my thoughts turn to my next task.