The "Twa Brigs" and Freight

In the prophetic poem by Robert Burns, "The Twa Brigs" (c 1780) he has the old bridge of Ayr, then under the threat of demolition, talk to the new bridge, just opened saying "I'll be a brig when you're a shapeless cairn" This came to pass some years later when the new bridge was indeed swept away in a flood!

The parallels with the present and the old Forth rail bridge (opened 1890) and the Forth road bridge, to be closed to heavy traffic, although it has not reached it's 50th birthday is cause for reflection. The original design life of the road bridge was 120 years. Were the design engineers incompetent or is there another reason for the failure?

How has this situation come about and how does it affect the mix of freight traffic moving by road or rail. A study of the history of freight transport gives some understanding of the present situation and how we can plan a way forward for the movement of goods, particularly as it relates to our special interest in the rail line to Caithness.

The Forth Joint Bridge Board was established by Act of Parliament in 1947, design work started in the early '50s. Construction work began in 1958, the bridge being opened in late 1964. The engineers' frame of reference of the early 1950s was a completely different one to that of today. Most long distance freight, moved by rail in vans of maximum 12 tons payload. Road freight in the main moved in 3 ton capacity four wheeled trucks, often delivering to and from railheads.

Until the mid 60s the A6 through Cumbria, carrying road traffic from the west of Scotland through Carlisle to Lancashire crossed a single track bridge controlled by traffic lights! 1958 saw the first motorway opening (the Preston bypass) and a gradual increase in truck gross laden weights (GLW) over the years from 16 to 22, 24 then 32 , 38, 40 and now 44 tons. The railways were stuck with outmoded capital stock and working practices. In 1961 prior to the Reshaping of British Railways Report (1963) "Beeching Report" the rail network carried 145 million tons of coal and 89 million tons of other traffic. Much of this traffic was abandoned and by the early 80s other than bulk loads it appeared that rail freight had no future. By 2004 rail tons lifted were 104 million tons mostly coal and aggregates.

The 1980 "Armitage" report into "Lorries, People and the Environment" recommended heavier lorries because it would lead to fewer lorries on the road. Between 1967 and 2007 the number of heavy goods vehicles (HGVs) fell from 593,000 to 446,000 as average annual loads and mileages increased. There were firm recommendations to control the dimensions and weight of lorries in the report. The maximum size of trailers then being 30ft, it is now 45ft. Conversely the proportion of revenues contributed by the heaviest trucks has significantly declined.

The engineering advice of the Department to the "Armitage" committee was that it would be unwise to permit any substantial increase in loads imposed on bridges over the then limit of 32 tons. The report, chose to ignore this advice but stated "people ask where will it all end? What is to stop there being subsequent increases to say 100 tons The answer is simple, it will end right here. The reason is bridges; 44 tonnes is the maximum weight of lorry that can be tolerated on the bridges of this country and it is an important part of our recommendations that there should be no further increases in maximum dimensions. We are sure the public would be well served by such a commitment." In the face of public opposition government restricted the increase to 40 tons but allowed 44 ton trucks to run to and from railheads. A few years later the 44 ton maximum was quietly approved.

Growing up at the Hurlet, outside Glasgow, in the 1950s I recall how little traffic there was at this now important intersection of the A726 and the A736. The only larger vehicles were Shell bitumen tankers from Ardrossan oil refinery. In the early 60s heavier lorries started to appear and a garden wall near this intersection, which had stood for over 100 years, collapsed.

Those responsible for the stewardship of national road network assets have failed to properly monitor the axle loading on roads. This could be easily carried out automatically. Poor distribution of loads may result in individual axles being grossly overloaded. The effects of this dynamic axle loading, particularly on damaged road surfaces is to the power of 8 of the axle weight. The bulk of the cost of road maintenance should be allocated to heavier lorries.

Another issue is that many early motorway bridges were built of low cost, high alumina, East German cement which has been for some time showing signs of distress and increased delays and congestion are likely as these are repaired. Some indication of a "market" rate for road use can be gleaned from the only toll road in the UK, the M6 toll round Birmingham. The current daytime charge is £5 for a saloon car (19p per mile), for a HGV is £10 each for 27 miles or 38p per mile.

From the 1920s government has viewed fuel duty and licence fees as a source of general revenue and not allocated or (hypothecated) to the road budget. Fuel duty raised £23.5 billion for the Treasury in 2004/05. Train operators operate on red diesel but more recently do pay some tax on this. Airline jet fuel is exempt under an international convention of 1947 although airline exhaust appears to be a major source of greenhouse gasses and damage to the ozone layer. In the 2008 DfT strategy for reducing greenhouse gas emissions says "each tonne of increase in CO2 will be met by a tonne reduction in another part of the economy."

UK government policy is to insist that freight is a commercial market and no subsidies will normally be provided. Support to freight users by the national DfT scheme to encourage the movement by rail of container freight under the now superseded Rail Environmental Procurements Scheme in 2008/09 was a token £3.7 million.

Another element in the attitude of policy makers is surely the history of intransigence of those representing the railway workforce. On a visit to Clyde Port Authority many years ago, I heard a perhaps apocryphal tale; the Greenock dockers had a coat of arms prepared which incorporated the wording "no today is more tomorrow." For them there was no tomorrow, as the traffic moved to more flexible ports such as Felixstowe. Unfortunately there appears to be a resurgence of this "head in the sand" approach.

The road haulage industry has been in the past very successful in externalising its costs. By this I mean road improvements which are driven by public demand for better roads are built to incorporate the engineering design requirements of the heaviest trucks.

In 2007 there were 248,000 casualties resulting from road accidents of which 28,000 were serious and a further 2,946 fatal. Fatalities involving HGVs was 435. There were no fatalities in rail accidents in 2009 although 3 road users were killed at level crossings. The costs of these accidents, in the main falls on the NHS, police, fire and ambulance services.

The demise of the Forth Road bridge has been caused by traffic levels and overloading that were never within the wildest imaginings of the designers, and stresses have allowed the corrosion of the supporting cables. No one has suggested that the haulage industry should bear the cost of the replacement bridge but in many other scenarios the "polluter must pay".

The stewardship of road assets can be contrasted with the Shin rail bridge on the Far North Line, where trains of oil tanks moving to Lairg fuel depot travel 1/3rd empty because of engineers' concern for the load bearing ability of the structure.

It is instructive that in the USA, federal policy is completely different. Despite our seeing US trucks of massive size on the TV, the maximum weight of trucks allowed on the federal interstate network is 40 tons; (individual states may have higher limits). There is also a network of weigh stations with regular monitoring of heavy traffic. There were a number of catastrophic bridge failures in the US due to overloading in the 1950s and this has led to a different attitude.

Another aspect of the working of the law of unintended consequences is that of the harmful effects of diesel exhausts and unburnt particulates. Exhaust scrubbing units are now mandatory in heavier trucks, as these fumes are very damaging to health, especially to children and now seen as a major cause of asthma and other respiratory problems.

The improvement of the productivity of the rail freight industry in the last 40 years has also been dramatic but slow to implement. In 1972 a "Transmark" report for HIDB was commissioned to investigate the establishment of a Freightliner depot in Inverness. The assumption made in this report was that the direct crewing required for such a service due to slow speeds of freight trains was 3 crews of 3 men (driver, second man and guard) each way, all workings unbalanced. That is all crews came back by passenger train. To move a Freightliner train from Inverness to Mossend, outside Glasgow, and back it was assumed, needed a total crew of 18 persons. It has taken 35 years to see rail container established in Inverness and single manning of freight trains in place.

Private road users on the A9 are delighted by the drop in traffic, with the removal of 20 or more Tesco trucks per day. However despite the fuel efficiency of a train being 4 times that of trucks and the crew savings (one driver rather than 20) the Tesco train still requires capital and revenue subsidy for viability, due to the costs of final collection and delivery.