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Railway Sleeper INFO

Railway sleeper facts & figures

  • Railway sleeper facts & figures
  • Railway sleeper facts & figures
  • Railway sleeper facts & figures
  • Railway sleeper facts & figures

How many railway sleepers are there in the UK?

With thanks to Ben Lavery for his curiosity & resourcefulness!!

17,645,400 give or take?!!

A few of weeks ago, I was sitting in a local café with my good friend Adam.  I can’t quite recall how we got onto the topic, but Adam turned to me and asked “How many railway sleepers are there in the UK?”. Not being able to tell him, he decided it would be my ‘homework’.  We laughed about it a bit, and somewhat forgot about it, but I was left pondering.  A couple of weeks later, questioning a couple of people at work, and using my Google-fu I was able to give Adam an answer.

My first source was a colleague, a man who has been working on the railway for many years.  He had no idea when I asked him, but helpfully said that in one chain there were roughly 22-23 timber railway sleepers.  So, with there being 80 chains to one mile, all I did was multiply 22.5 by 80, with the result of 1,800 sleepers per mile.? My second source was the Office of Rail Regulation.  They publish a Current National Rail Trends yearbook (downloadable).  During the period 2010-2011, it claimed that there was 15,777km of track open to both passenger and freight traffic, this equates to roughly 9,803 miles of track.? Armed with these figures, I multiplied 9,803 miles by 1,800 sleepers per mile to give me an approximation of 17,645,400 railway sleepers on open railway in the UK. ?I presented my findings to the surprised but seemingly impressed Adam last Thursday, stressing that it is only an approximation, as it doesn’t cover sidings, depots, etc. It also assumes that all terrain is the same, and that all the railway sleepers are made of the same material, and that they have all been installed 100% accurately.

A surprising fun research exercise, it was good to get Googling for answers to seemingly impossible questions!

What are railway sleepers made of NOW ?   AND The FUTURE ?

With thanks to Chris Lo for a great article

The way forward?
Wood, Concrete, steel or plastic ?

With ongoing track replacement and upgrades being carried out around the world, the railway sleeper market is huge. Chris examines the materials being used, from traditional timber to ultra-modern composites.

Railway sleepers, or railroad ties as they are known in the US, are a somewhat unglamorous component of the rail industry. But these blocks, which are laid horizontally underneath tracks to hold rail lines in place at the correct gauge, form the backbone of rail travel. Millions of these vital blocks are manufactured and distributed every year to satisfy demand for network expansions and line upgrades.
Apart from some experiments with stone block sleepers at the earliest stages of rail transport's development, timber has been the historically dominant material used for railway sleepers. Through the 20th century, new materials have emerged to respond to the need to accommodate higher axle loads and faster speeds. Here, we weigh up the advantages and disadvantages of the materials on offer.

Wooden sleepers
Given that wood has been used for the better part of two centuries to make railway sleepers, it is surprising that wooden railway sleepers still comprise the majority of the railway sleeper market. This is particularly the case in the US, where wood has a 93% share of the market – 16 million wooden railway sleepers are laid every year.
It's no accident that timber's market ascendancy has never waned. The natural properties of wood (usually hardwood such as oak, but cheaper softwood has been used on lighter, less busy lines) are suited to providing a resilient track with excellent dynamic attenuation of impact loading as well as noise and vibration reduction.
"Railway sleepers are laid horizontally underneath tracks to hold rail lines in place at the correct gauge."
Wooden railway sleepers are also comparatively cheap, as well as light and easy to transport, install and maintain. The average timber railway sleeper weighs around 160lb-250lb, whereas an equivalent sleeper made of concrete could weigh anything up to 800lb. This means that wooden railway sleepers are quicker and easier to install initially and require little to no specialist equipment or vehicles for maintenance, which means cost-savings for rail operators.
Proponents of timber for railway sleepers have also pointed to the strong second market for disused wooden railway sleepers. There is a booming business for reclaiming used railway sleepers as a hardy material for gardening and landscaping or to use as biomass fuel for cogeneration power plants. However, the majority of timber railway sleepers are soaked in coal tar creosote in order to protect them from environmental wear and insect infestation. Creosote extends the life of wooden sleepers (untreated timber sleepers usually have to be replaced every seven to 12 years) but is a toxic hazard which creates an added cost for disposal and has damaged the environmental credibility of the industry's traditional railway sleeper material.

Wood is also far more susceptible to wear and tear than more modern sleeper materials. Operators are increasingly replacing timber with concrete or composites in areas where sun and damp can warp or rot timber.

The case for concrete railway sleepers
Although concrete railway sleepers have captured only a small fraction of the market in the US, in Europe and Japan, where rail transport is arguably a higher priority, concrete railway sleepers have been gaining ground since the end of World War II. In Australia, concrete is used for most railway sleepers, and in the UK, rail operator Network Rail replaces 200,000 wooden railway sleepers with concrete ones every year.
Concrete sleepers are generally made from cast concrete slabs reinforced internally by steel wire. Early prototypes made with conventional reinforced concrete were often found too brittle to withstand high levels of dynamic load. Modern concrete railway sleepers are primarily manufactured using pre-stressed concrete – a technique where internal tension is introduced to the railway sleeper (usually to the high-tensile steel wire skeleton) before it is cast to counteract the external pressure the blocks undergo during service.
Concrete manufacturers such as Abetong Teknik, INFRASET and Stanton Bonna have made a strong case for the performance of concrete in the railway sleeper market. The material requires less maintenance and has a longer service life than timber sleepers, as it is not prone to environmental degradation, warping or insect infestation and its non-combustible nature means it lessens the potential for track fires.
"Timber has been the historically dominant material used for railway sleepers."
Pre-stressed concrete sleepers can also boast a generally superior load capacity and a smoother ride as a result of their greater weight and vertical / lateral stability. For the most modern high-speed lines, concrete (or composite plastic) becomes a necessity to bear higher speeds
But critics have been quick to point out that the weight and bulk of concrete railway sleepers is a significant disadvantage when it comes to the cost – both in time and money – of initial installation and later repairs.
While wooden railway sleepers can be put in place fairly quickly and with little specialist equipment, concrete sleepers must be installed using heavy machinery.
As pre-stressed concrete requires a skilled workforce and specialist equipment to manufacture, this high-quality material is certainly not a cheap option, although concrete manufacturers argue that the durability of the material means higher value over the lifespan of concrete sleepers.

Limited adoption of steel railway sleepers
Steel railway sleepers are often seen as a middle ground between wood and concrete. Sturdier than timber and less expensive than pre-stressed concrete, it seemed logical that steel could prove a boon to companies looking to undertake an economical track upgrade. Indeed, in some areas steel ties are still performing adequately after 50 years of service. A lesser reliance on ballast (approximately 60% less than required for concrete; 45% less than wood) also seems to tip the scale in steel's favour, especially in areas where timber is scarce.
But a number of unique problems have limited the adoption of steel for railway sleeper applications, especially in the US with its abundance of natural timber resources. Steel railway sleepers are susceptible to corrosion and rail operators have reported in the past that steel ties have been removed from tracks after rail seats became quickly fatigued, especially on lines with many turns.
"Concrete railway sleepers are generally made from cast concrete slabs reinforced internally by steel wire."
Capital Metro, the transit authority for Austin, Texas, provides a good example of another common problem specific to steel railway sleepers – the lack of insulation. Neoprene composite insulation keeps steel railway sleepers separate from electrified rails, but any error can wreak havoc on a rail network. A report in the Austin American-Statesman in March 2010 noted that as a result of conductivity problems and signal failures, Capital Metro has been forced to replace long sections of steel railway sleepers with timber at an additional cost of $90,000. "I wish I'd never done it," Capital Metro railroad manager Bill Le Jeune told the newspaper.

Plastic composite railway sleepers: the material of the future?
The most modern material being used for railway sleepers, plastic composite, represents manufacturers' latest attempt to find a material that fulfils the necessary criteria without any significant drawbacks. Composite railway sleepers are made from various mixtures of raw materials (plastic, rubber from used tyres, waste fibreglass) to create a synthetic material with the pliability and accessibility of wood, coupled with the durability of concrete.
Japan has been a leader in composite manufacturing. Japanese manufacturer Sekisui Chemical provided fibre-reinforced foamed urethane (FFU) railway sleepers for the Shinkansen high-speed train. 90,000 FFU sleepers are laid every year in the country, with nearly 1.5 million in current service.

Sekisui's composite railway sleepers made their European debut in 2004 when they were installed on the tracks of the Zollamt Bridge in Vienna, Austria. The material was chosen for the bridge because it matched the performance of wood while remaining unaffected by temperature changes and the constant moisture hanging in the air.
The advantages of composites are clear – the material can be manipulated and sawed just like wood, without any of the inbuilt disadvantages of its all-natural counterpart. It has the durability of concrete (composites have a service lifespan of 50 years or more), without concrete's weight and ponderous installation process. Unlike concrete railway sleepers, for which a track must be completely overhauled, composite railway sleepers can be installed piecemeal alongside older timber models.
"Composite railway sleepers are made from various mixtures of raw materials."
Composite railway sleepers have the additional advantage of being made from mostly recycled material, and are fully recyclable (they can be recycled into new sleepers). A 2006 report by the waste and resources action programme (WRAP) notes that a mile of wooden railway sleepers requires 810 mature oak trees, while an equivalent length of composite sleepers uses two million plastic bottles, 8.9 million plastic bags and 10,800 post-consumer tyres that could otherwise end up in landfill.
It's clear that composite material (or a derivation of the technology) holds the key to creating a widely adopted, environmentally friendly and operationally efficient substance for the railway sleeper industry. Cost concerns have generally limited its use to lines where timber and concrete are unsuitable, but as the manufacturing process becomes more refined and affordable for the sleeper market it seems there will be little standing in the way of composites catching up and overtaking timber as the railway sleeper material of choice.

Advantages of wooden railway sleepers over concrete ones

Benefits of wooden railway sleepers versus concrete / steel railway sleepers.

1.      Transportation: When in transit and during handling, railway sleepers are likely to bear hits and knocks, wood is better able to withstand surface damage whereas the galvanised face of steel is thin and can easily be damaged leaving the steel open to the elements and causing rust.
2.      Ease of Machining:  The ease of which timber can be machined means companies are able to tailor their stock & range of railway sleepers to individual requirements and specifications. Bespoke design is a much more costly and time consuming process when dealing with steel and concrete.
3.      Ease of Installation and Maintenance: Timber is a lighter material that steel or concrete, making it easier to handle. This means that the installation time and man power required is greatly reduced, saving money throughout the life of a railway sleeper, as it is lighter and far easier to maintain and handle, should it require any attention.
4.      Cost Saving: Wooden railway sleepers are less expensive that steel in many areas. These include the raw material cost and transportation. Furthermore timber railway sleepers are easier to install and modify on site, meaning that money will constantly be saved throughout the life cycle of a railway sleeper through reduced maintenance costs.
 

Going back in History - railway sleepers  80 years ago
 

The production, import & export of railway sleepers during the 1st / 2nd World Wars.

This is what was written then:
"It is estimated that there are at present throughout the world about 1,250,000 kilometres of railway track for which approximately 3,000 million railway sleepers (crossties) are used, 95 percent of them made of wood. Since railway sleepers are heavy, bulky, and relatively cheap, they do not ordinarily comprise a large portion of the international trade in wood.

Types of railway sleepers The term railway sleepers refers to the rectangular or approximately rectangular cross section supports laid transversely on the railway roadbed to support the rails. Railway sleepers used in Europe are almost exclusively of wood and are manufactured either in sawmills or in the forest. Production at the felling site in the forest is gradually declining in importance as a result of the disappearance of skilled labour. Axe-hewn, squared railway sleepers, which are frequently used in the Americas and other parts of the world, are not produced in Europe. 

Railway sleepers may be made of hardwoods or softwoods, these being used for different purposes and under different conditions. Hardwood railway sleepers are made chiefly from oak, beech, and hornbeam; softwood railway sleepers from Scots pine, maritime pine (Pines pinaster), and larch. In Spain, eucalyptus is also used to make railway sleepers. Railway sleepers are usually cut from trees of 80 to 120 centimetres in circumference at a height of 1.30 meters from the ground, or from the tops and branches of large trees found in high forest or coppice with standards. 

Standard gauge railway sleepers (1.46 meters) used in Europe may be classified into three different categories: German railway sleepers measure 16 cm. x 26 cm. x 2.6 m. or 2.7 m.; French, 14 cm. x 26 cm., and the same length; English, 12.5 cm. x 25 cm. These figures apply to railway sleepers sawn on all four sides. However, a certain amount of latitude is allowed for wane and curvature, there being three or four specifications. There are also the so-called "Swedish" or "Saxon" sleepers, where the upper and lower surfaces are sawn but the sides follow the natural contour of the rough log. 

Switch or crossing railway sleepers vary in length from 2.60 m. to 5 m. or more; industrial railway sleepers are 1.80 m. to 2 m., and crossings generally 1.30 m. to 2 m. 

The useful life of a railway sleeper depends upon its resistance to fungi, insects, and mechanical pressure. Protection against decay is obtained by impregnating with chemicals. The most widely used impregnating material is creosote, but solutions of copper or zinc salts are also used. By impregnation the useful life of a railway sleeper can be increased from 5-8 years to 25-30 years. Sleepers must have certain required mechanical properties. Damage to railway sleepers due to mechanical defects has become more frequent because both the weight of the loads carried and the speed of trains have increased. Such mechanical damage consists mainly in crushing, splitting, becoming imbedded, etc. "

The railway sleeper market between the two world wars
Data on international trade in railway sleepers between World Wars I and II can be found in the yearbooks of the Comité International du Bois, published first at Vienna and later at Brussels; in the publications of the International Institute of Agriculture, and in Silvae Orbis, referred to in Tables below.

IMPORTS OF RAILWAY SLEEPERS BETWEEN THE TWO WORLD WARS 

Country 

1926-28
Average 

1931-33
Average 

1936-38
Average 

1000 m³ (s) 

Belgium-Luxembourg 

67 

38 

84 

Czechoslovakia 

35 

12 

Denmark 

24 

15 

France 

16 

76 

Germany 

411 

17 

69 

Greece 

Hungary 

57 

34 

Netherlands 

72 

77 

76 

Spain 

160 

30 

... 

Switzerland 

United Kingdom 

346 

337 

540 

China 

41 

135 

105 

Canada 

51 

24 

20 

United States 

94 

37 

32 

TOTAL 

1,386 

803 

993 

SOURCE: Walter Grottian, "Die Umsatzmengen im Weltholzhandel 1925-1938" Silvae Orbit, Berlin: C.I.S., 1942, pp. 140-141. Computed from yearly figures. 

EXPORTS OF RAILWAY SLEEPERS BETWEEN THE TWO WORLD WARS 

Country 

1926-28
Average 

1931-33
Average 

1936-38
Average 

1000 m³ (s) 

Austria 

87 

13 

Czechoslovakia 

30 

... 

Finland 

16 

France 

119 

28 

93 

Germany 

49 

34 

Poland 

364 

157 

255 

Rumania 

27 

Sweden 

47 

19 

11 

Yugoslavia 

281 

80 

90 

Baltic States1 

15 

47 

144 

U.S.S.R. 

96 

282 

186 

Canada 

115 

67 

92 

United States 

336 

153 

173 

Turkey 

... 

TOTAL 

1,567 

874 

1,096 

SOURCE: Walter Grottian, "Die Umsatzmengen im Weltholzhandel 1925-1938," Silvae Orbis, Berlin: C.I.S. 1942, pp. 140-141. Computed from yearly figures.

The principal exporting countries were Poland, Yugoslavia, the Baltic countries, Rumania, and Soviet Russia. The U.S.S.R. exported as much as 579,000 m³ (s) of railway sleepers in 1930. The United States of America exported large quantities to the European market. France had some exports but was a net importing country. Its exports of hardwood railway sleepers went mainly to Belgium, with lesser quantities to the Netherlands and the French colonies; softwood railway sleepers were shipped principally to the United Kingdom and in small quantities to Spain, Belgium, Luxembourg, and the Netherlands. 

European imports attained a maximum figure of 1,653,000 m³ (s) in 1930 and decreased thereafter. This drop in trade corresponds to a general worldwide trend. Railway sleepers constituted 2.5 percent of all timber exports in 1929 but only 1.9 percent in 1937.

International market after world war II

During the war most European countries were unable to carry out much track maintenance or lay new railway sleepers. Consequently the railway sleeper market was quiet and countries attempted to supply their own needs from domestic production. Owing to shortages of chemical products, few impregnated sleepers were used. 

After the end of the 2nd world war, there was a great demand for railway sleepers, due not only to deferred maintenance requirements and the need for replacement of non-treated railway sleepers which had deteriorated rapidly, but also to the vast amount of destruction caused in the last year of the war by military action. Such destruction particularly affected France, Belgium, the Netherlands, Italy, and Soviet Russia, but there was also a considerable amount of damage in Africa, from Morocco to Egypt.  

REQUIREMENTS OF WOODEN RAILWAY SLEEPERS AFTER THE 2ND WORLD WAR 

Country 

Requirements 

Length of railway lines 

Railway sleepers 

Round wood 

Requirements known 

km. 

in thousands

1000 m³ 

 

Germany: French zone 

7,200 

200 

28 

 

Austria 

7,500 

1,100 

150 

 

Belgium 

8,000 

1,500 

1 215 

 

Denmark 

3,000 

455 

1 65 

 

France 

62,000 

7,700 

1,100 

 

Italy 

20,500 

² 3,500 

500 

 

Luxembourg 

500 

41 

 

Norway 

5,000 

450 

1 65 

 

Netherlands 

5,000 

³ 1,000 

1 143 

 

Poland 

35,000 

3,000 

1 430 

 

Czechoslovakia 

14,900 

1,700 

240 

 

Subtotal 

168,600 

20,646 

2,942 

 

Average per km. 

 

122,5 

16,3 

Requirements unknown 

 

 

 

 

Germany: 

 

Bizone 

36,000 

 

 

 

Soviet zone 

15,700 

 

 

 

Bulgaria 

3,400 

 

 

 

Greece 

1,500 

 

 

 

Hungary 

8,500 

 

 

 

Rumania 

10,500 

 

 

 

Sweden 

8,400 

 

 

 

Switzerland 

4,300 

 

 

 

Yugoslavia 

10,100 

 

 

 

Subtotal 

98,400 

 

4 1,600 

 

Total 

267,000 

 

4,542 

 

United Kingdom 

59,100 

5 4,000 

570 

GRAND TOTAL 

326,100 

 

5,112 


EXPORTS OF RAILWAY SLEEPERS AFTER THE 2ND WORLD WAR

Exporting country 

1946 

1947 

Jan.-June 1948 

1000 m³ (s) 

Austria 

Czechoslovakia 

27 

4,9 

Finland 

13 

1,0 

France 

19 

15,1 

Germany: 

 

 

 

 

British zone 

 

French zone 

... 

... 

... 

 

American zone 

... 

... 

... 

 

Russian zone 

... 

... 

... 

Norway 

Poland 

1- 

Portugal 

... 

... 

Sweden 

52 

²36 

12,7 

Switzerland 

... 

... 

Yugoslavia 

... 

... 

... 

Other European countries 

+10 

... 

... 

U.S.S.R. 

... 

... 

... 

Canada 

113 

222 

188,5 

U.S.A. 

+63 

³410 

124,7 

TOTAL 

249 

... 

... 

SOURCE: FAO/ECE, Timber Statistics for the Years 1946-1947, Geneva, March 1948, and Timber Statistics, Quarterly Bulletin, Vol. I, No. 2, Geneva, October 1948. 

IMPORTS OF RAILWAY SLEEPERS AFTER THE 2ND WORLD WAR 

Importing country 

1946 

1947 

Jan.-June 1948 

1000 m³ (s) 

Belgium 

36 

35 

1,5 

Denmark 

12 

7,0 

France 

21 

82 

22,3 

Greece 

0,7 

Hungary 

23,0 

Italy 

28,9 

Netherlands 

48 

80 

120,9 

Poland 

... 

Switzerland 

7,7 

United Kingdom 

84 

297 

120,1 

Other European countries 

14 

16,0 

Egypt 

+14 

... 

13,0 

Other Middle East countries 

... 

French North Africa 

+6 

... 

... 

TOTAL 

226 

... 

SOURCE: FAO/ECE, Timber Statistics for the Years 1946-1947, Geneva, March 1948, and Timber Statistics, Quarterly Bulletin, Vol. I, No. 2, Geneva, October 1948.

United States exports started expanding in April 1947, particularly when non-treated railway sleepers were eliminated from the list of controlled export commodities and were placed on the list of commodities requiring only a license. Treated railway sleepers remained on the controlled list, and in 1947 only one million treated sleepers were exported. In the first quarter of 1948, United States exports of treated and non-treated railway sleepers amounted to 23.6 million board feet - a monthly average of approximately half of that for the year 1947.

UNITED STATES EXPORTS OF RAILWAY SLEEPERS - ANNUAL AVERAGE 1935-1939 

Country of destination 

Quantity 

Value 

Treated sleepers 

Non-treated sleepers 

Total 

Treated sleepers 

Non-treated sleepers 

Total 

1000 board feet 

dollars 

China 

36,459 

36,459 

480,090 

480,090 

Canada 

5,581 

1,573 

7,151 

225,370 

41,006 

266,376 

Guatemala 

5,155 

5,155 

159,092 

159,092 

Costa Rica 

3,767 

3,769 

129,223 

39 

129,268 

Peru 

107 

3,535 

3,642 

1,942 

104,146 

106,088 

Honduras 

3,515 

3,520 

105,404 

107 

105,511 

Cuba 

2,216 

15 

2,231 

83,377 

374 

83,761 

Mexico 

973 

1,181 

2,154 

40,270 

30,589 

70,859 

Panama 

1,964 

1,965 

74,704 

56 

74,760 

Venezuela 

214 

37 

251 

6,754 

776 

7,529 

Netherlands 

184 

184 

2,060 

2,060 

United Kingdom 

99 

37