They are the unglamorous machines that slave away in the background, often around the clock, day in and out, generally unseen by the travelling public, except if one is a keen rail enthusiast with an eye for rail yards and sidings. A dying breed in these days of reduced freight carriage by rail the world over, of vanishing marshalling yards and sidings, of modern multiple unit bi-directional passenger trains which require no assembly and dis-assembly. They are the shunting locomotives which have contributed in no small measure in keeping the railroads operating since the earliest days of the advent of the iron horse. For a die-hard rail fan it is just as exciting observing a shunting locomotive at work, be it steam its driving wheels spinning violently as it tries to get a grip on the rails, or if diesel its engine revs rising from a leisurely idle to a deep throb in notch 8 as it exerts full tractive effort on a long rake of wagons, as seeing an express locomotive thunder past with a named train.

The Wikipedia defines shunting in railway parlances as the process of sorting items of rolling stock into complete trains, or the reverse. In North America, the activity is known as “switching” and shunting locomotives are termed “switchers”.

E D Gilmour once writing in “Model Railway News” indicated that shunting could refer to many kinds of operations in the railway world; it could mean a freight train en route may be shunted into a refuge siding to allow a higher priority train to pass; a passenger train after arriving at a station may be shunted to a siding. There is also the shunting of wagons as distinct from whole trains. An arriving train is broken up or marshalled; its wagons could be shunted into sidings, ready for their next trip, or those that are not ready, being put back. Wagons could also be placed in position for different procedures, such as for loading or unloading under cranes or at a dock, or for some other intended work. Then there is always the making up or assembly of trains by adding together items of rolling stock. The accepted arrangement at most marshalling and holding yards is for a shunting locomotive to assemble the train, be it goods or passenger, in a siding to await the arrival of the guard and train locomotive for either proceeding on its way, or for transfer to the station platform, as the case may be.

In very early times of the railways, particularly prior to the 1890s, when wagons and carriages were far less heavy than in later years, horses had been employed for shunting in countries such as Britain and the US. With the rapid increase in size and weight of rolling stock, the use of horses became impractical and railways had to resort to using locomotives for shunting. Due to many rail yards especially at docks and collieries having restricted clearances with lightly laid track coupled with sharp curves, specialised shunting locomotives, generally of the tank type, with short wheelbases, came into prominence. Speed was not an issue, but higher tractive effort was a requirement. Tank engines had better rearward visibility, reduced length and better adhesion for a given size in comparison with tender types, criteria ideal for shunting purposes. Many shunting steam locomotives were equipped with reversing levers rather than with screw reversers. The lever could be thrown over very quickly whereas the screw reverser had to be turned through numerous turns before the driver could open the regulator and begin to move, rapid change of direction being a more than desirable requisite in shunting.

The earliest records of shunting locomotives in Sri Lankan railways date back to 1874 when two 0-4-0 saddle tank locomotives earlier working on the Break-water Line were taken over (refer to “Railways of Sri Lanka” by David Hyatt). (It is to be noted that this article is confined to Broad Gauge locomotives of Sri Lanka). Subsequently, beginning from 1898 a number of 0-6-0 tank locomotives were obtained from different manufacturers in Britain such as Dubs and Hunslet, mainly for shunting purposes but used also for other duties. In the 1920s these locomotives had been rebuilt locally at the railway workshops into 0-6-2 tanks with the addition of a pony truck under the bunker. The railway also received an additional five 0-6-2 tanks from Robert Stephenson & Co in 1928 to complement the shunting locomotive stocks. With the reclassification scheme of 1937 all the 0-6-2 locomotives came under the E1 Class, with suffixes attached according to year of manufacture. They weighed around 47 tons, had non-superheated boilers with tractive efforts of 18,014 lbs and were equipped with Stephenson inside valve gear (refer to Fig 1). They lasted well into the end of the steam era some having spent their entire lives attached to important rail hubs. The writer remembers E1C Number 24, the shunter at Kandy, its shrill whistle reverberating for miles around as it clanged and banged its way around the yard throughout the day and well into the night. During its absence for prolonged periods, possibly occasioned by major overhaul, a Class B8 usually deputised. E1 Number 93, built in 1898 and which had been the oldest operational steam locomotive in Sri Lanka spending most of its life at Rambukkana, is displayed at the Kadugannawa Rail Museum.

At the beginning of the 1900s, in order to cope with the increasing passenger demand around Colombo, several large 2-6-4 tank locomotives were ordered from Robert Stephenson and Hawthorn Leslie for the suburban passenger services. The earliest of these arrived in 1907 and the last as late as 1931. Additional to the passenger working these were employed on heavy shunting around the Colombo and Maradana yards. The initial batches later classified as Class D2/D3, had Stephenson inside slide valve gear, while the later ones had outside Walschaerts motion and bore the Class D1 classification. Some of the D1s were named after leading schools in Colombo. They were powerful engines weighing 75 tons and boasting tractive efforts of 21,275 lbs (refer to Fig 2); able to take in their stride fully loaded fourteen coach passenger trains. With the hasty introduction of the diesel multiple units (‘power sets’ as termed in Sri Lanka) in the mid to late 1950s these once proud and handsome kingpins of the suburban passenger scene were stripped of their responsibilities, to while away the twilight of their lives, totally relegated to shunting duties until scrapped in the 1960s.

Shunting is inherently a highly hazardous operation. In countries such as Sri Lanka where the use of chain and screw type couplings with buffers persisted into the late twentieth century, the risk was even higher. Personnel had to get in between wagons and carriages to couple and uncouple. The arrival of the auto coupler reduced the risk to some extent, but the type of some of the couplers used does not preclude uncoupling without still getting in between vehicles. In Sri Lanka, generally for shunting purposes the brake piping (vacuum till recently with air being introduced on newer carriages) is never connected, the engine brakes being relied upon for stopping. However if a main line train is involved in shunting en route, the brake piping is intact. Fly shunting (or loose shunting) where a string of wagons is propelled by an uncoupled locomotive to various lines is also resorted to, avoiding the need for having to proceed up and down each line.

The very first diesel shunting locomotive on the then Ceylon Government Railway was the 20 ton 0-4-0 diesel electric built by Armstrong Whitworth in the UK in 1934. Classed as G1 and numbered 500, it had an Armstrong-Saurer 6BXD 122 bhp diesel engine de-rated to 116 bhp with jackshaft drive and was capable of hauling 500 tons around 5 chain radius curves at 5 mph. It worked throughout its whole life at the Ratmalana Railway Workshops until withdrawn in the 1990s. Due to a connecting rod smashing through the crankcase it had been re-engined in 1959 with a Rolls-Royce C6 SFL 127C engine. Fig 3 shows the locomotive as displayed currently at the Kadugannawa Rail Museum as a static exhibit.

The next batch of diesel shunters were the Class G2 North British built 54 ton Bo-Bo diesel electric locomotives introduced in 1951, totalling eight in number. Their 625 bhp Paxman 12RPHXL engines had been later de-rated to 395 bhp in Ceylon. At their original rating they developed an impressive starting tractive effort of 35,000 lbs. Although initially intended for heavy shunting and local and branch line duties, their traction motor gearing limited them to a maximum speed of only 20 mph preventing their regular use on applications other than shunting. However it is learnt that they were occasionally used in hauling freight to far away destinations such as even Kandy. They continued to perform shunting duties in the Colombo and Beira inward yards before being finally withdrawn in the early 1980s. Figure 4 shows a G2 hauling a goods train near Colombo in the early 1950s. One in the Class, Number 535 is preserved at Bandarawela station.

It was not until 1969 that the Sri Lankan railways were again able to procure locomotives meant specifically for shunting. These were the Class Y Hunslet built 0-6-0 (or 0-C-0 under diesel wheel classification) diesel hydraulic locomotives and remain the last such batch to be secured (refer to Fig 5). They are powered by 530 bhp Rolls-Royce DV8 diesel engines and weigh 45 tons. A total of 28 locomotives were obtained with many working in the Colombo yards and some sent to major out-station locations. Restricted to a maximum speed of 37 kmph, they are also used in branch line duties around Colombo. It is understood that all except one in the Class still remain in operation when ironically, almost all main line diesel hydraulic locomotives acquired at the time were scrapped after a relatively short life span. Mention needs to be made of two note-worthy undertakings at constructing diesel locomotives locally, intended mainly for shunting. The first was in 1955 when a 47 ton diesel electric with Bo-Bo wheel arrangement and numbered 589, was constructed utilising two of the 180 bhp English Electric Willans H6 Type engines once used on the Class S1 diesel multiple units which arrived in 1938 (refer to Fig 6). An identical second locomotive, numbered 590, was turned out in 1958. Additional to shunting, they are said to have been used on local passenger service as well prior to being scrapped nearly a decade later. The second effort came in 1972 when seven 0-8-0 diesel hydraulic locomotives were manufactured with Paxman 12YJXL engines of 1,080 bhp. Weighing 52 tons they had a maximum speed of 48 kmph. Employed both in shunting and local passenger and goods service, all had been scrapped by the 1980s. One in the Class is preserved at the Kadugannawa Museum. These endeavours are seen as bold initiatives when at one time the railways were not held back from venturing out into territory hitherto unexplored.

This article although concentrating mainly on the shunting scene in Sri Lanka, would not be complete without briefly exploring the trends overseas, especially Britain and the US.

During the steam era, numerous tank locomotives of varying wheel arrangements came to be employed for shunting on the rail yards of Britain, beginning from the late nineteenth century. After the grouping of the railways into the ‘Big Four’ companies in 1923, each company developed their own line of shunters, mainly 0-6-0 tank locomotives, from either existing designs or new ones suited for their individual needs. Some well-known examples were; the Fowler 3F Class 0-6-0 (known as ‘Jinties’) tank engines weighing 50 tons with tractive efforts of 20,835 lbs manufactured between 1924 and 1931 on the London Midland and Scottish Railway (refer to Fig 7), the famed Great Western 0-6-0 Pannier tanks, 47 tons in weight and developing 22,515 lbs of tractive effort built from 1925 to 1950 and the London and North Eastern Railway J68 0-6-0s, weighing 43 tons, developing 19,091 lbs tractive effort and constructed between 1912 and 1923. All these classes numbering in their hundreds, hauled branch line freight and passenger services additional to shunting, several lasting right to the end of the steam era.

The classic British diesel shunter was the 0-6-0 type classified into Classes 08 to 12, the history of which dates back to the London Midland and Scottish Railway days of the 1930s (refer to Fig 8). Designed in 1934, they continued to be built in several hundreds and in numerous variations up to 1962, well into the British Rail period. Most of these diesel electric shunters were equipped with English Electric 6KT diesel engines developing 350 bhp, weighed around 50 tons with a starting tractive effort of 35,000 lbs and were confined to a maximum speed of 20 mph. A number were exported to other European countries and many are still in active service on the present privatised railways of Britain.

In the US, shunters or switchers as they were termed developed on completely different lines due to the gargantuan nature of the loads handled by the railroads from the earliest times. Steam switchers came in all shapes and sizes from wheel arrangements of 0-4-0 to gigantic 0-10-0s some weighing more than 150 tons, generally of the tender type as tank engines never found favour over in North America. Steam switchers continued to be used till the demise of steam in the late 1940s and early 1950s. Figure9 shows a 0-6-0 switcher built by the Southern Pacific Railroad in 1921 with a total weight of around 100 tons and tractive effort of 30,000 lbs, now displayed at the Travel Town Railroad Museum in Los Angeles.

Diesel switchers began coming to the forefront in the US in the 1930s when the Electro Motive Corporation (later Electro Motive Division [EMD] of General Motors) introduced their line of switching locomotives. Although ALCO and other manufacturers followed suit with their own versions, EMD dominated the diesel scene in the US for the next several decades and their SW line of switchers had an almost monopolistic control of the switcher market. Powered by the legendary EMD 567 engine in various cylinder combinations in power outputs up to around 1,600 thp, these switchers were known for their reliability, ruggedness and long life. Many such types are still in use today after several decades of service.

Especially in the US, large classification yards (or marshalling yards as termed elsewhere) came to be established from the early twentieth century for separating freight wagons (or cars as called in North America) into different tracks for the purpose of disassembly of trains and sorting for loading or unloading and transfer. Immense freight trains often miles long are also assembled in these yards, with many of the yards being several hundreds of acres in extent. The Union Pacific’s Bailey Yard in North Platte, Nebraska covering 2,850 acres is said to be largest classification yard in the world capable of handling 10,000 freight cars a day (See Fig 11 for photo). Often these yards employ the process of ‘Hump Shunting’ where cars are pushed on a rising gradient over a hump onto a falling gradient on the other side giving the vehicles enough momentum to roll into required sidings. Retarders, either pneumatically or hydraulically operated and computer controlled, which grab the vehicles’ wheels are used for controlling the speed on the downward gradient.

These sprawling yards require dozens of switchers for the movement of cars. In addition to the traditional switcher type locomotives, numerous ex-main line units such as EMD 3,000 thp SD 40s and 2,000 thp GP 38s, now demoted to switching duties, are employed often in multiple unit combination (refer to Fig 10).

A new development that has been unveiled in the US in recent times has been the gen-set locomotive intended for both switching and branch line working. These locomotives utilise multiple diesel engines, sometimes as many as three, whereby a single engine or a combination can be powered up dependant on the load requirements, resulting in reduced emissions and improved fuel efficiency. Figure 12 shows a gen-set locomotive manufactured by the National Railway Equipment Co (Model 3GS21B) fitted with three Cummins QSK19C engines, each developing 700 thp in sparkling BNSF colour scheme.

In Sri Lanka, in comparison with the age of steam, the number of shunters in use has declined sharply and today is confined to the twenty odd Class Y Hunslets still in operation. This is a phenomenon observed worldwide since the late 1900s, due to contracting networks, increased competition from road traffic and widespread adoption of train-load freight, with fixed rakes of wagons moving mainly bulk products instead of many sidings and goods depots feeding trains of assorted wagons. In the case of passenger traffic, virtually throughout the world the fixed consist diesel or electric multiple unit is reigning supreme, precluding the making up of complete passenger trains for locomotive haulage.

Shunting locomotives, the round-the-clock workhorses toiling away unseen and once the mainstay of many a railroad may be in decline. However, as long as railroads exist and goods and freight needs to be moved, many of these die-hard stalwarts will continue to survive.

Reference:

• “Railways of Sri Lanka”, David Hyatt, Comrac London & Colombo, 2000
• “Armstrong Whitworth, A Pioneer of World Diesel Traction”, Brian Webb, Lightmoor Press, UK, 2010
• “Train Shunting and Marshalling”, Bob Essery, Ian Allen, UK, 2011
• “North American Railyards”, Michael Rhodes, MBI, Minnesota, 2003
• Photographs: Figs 1 & 2 courtesy of Flickr,
• Figs 3 - 5 courtesy of David Simon,
• Fig 6 courtesy of Sri Lanka Railways
• Figs 7 & 8 and 10 - 12 courtesy of Rail pictures Net
• Fig 9 Author’s own