The history of massive smoke emission as a result of fuel burning in Kenya can never be told without mentioning the railway. It was in fact the railway that gave birth to what today is known as the republic of Kenya. And as Sir Charles Elliot, Commissioner for East Africa Protectorate said in 1903, “it is not uncommon for a country to create a railway, but it is uncommon for a railway to create a country. The railway was the first “modern” form of mechanized transport in East Africa. It was built in Kenya many years before the Wright brothers took to the air in 1903.

Following the terms of the Berlin conference of 1884, European powers divided Africa into spheres of influence. The British East Africa Protectorate was declared in July 1895.Each power was required to stop slavery and slave trade in its protectorate, and instead develop infrastructure in their respective territories. A sure way to fight slave trade in Kenya was to construct a railroad running parallel to the slave route from Mombasa to Uganda. “You will never have struck a blow at it (slave trade) so fatal and so direct as the construction of this railway that the Government has set foot” said Lord Rosebery, Leader of opposition, in August 1896.

However, the plan was opposed by some parliamentarians led by Henry Labouchere who in his famous poem lamented,
“What is the use of it, none can conjecture,
What it will carry, there is none can define,
And in spite of George Curzon`s superior lecture,
It is clearly naught but a lunatic line.”
*Lord Curzon was the British Foreign Minister at the time.

On 11th December 1895, Eng. George Whitehouse arrived at Mombasa with the mandate of the Uganda Railway Committee in London to build the “Lunatic line”. He was a veteran of railway building having served as Chief Engineer in Mexico, South Africa,South America and in India. The first rails were laid at Kilindini on 30th May 1896. Whitehouse soon ran into a series of problems the first being lack of a deep water harbor in Mombasa that would be used to unload tons of construction materials and for landing the estimated 320,000 Indian coolies who would do the actual laying of the rail. Other obstacles were lack of fresh water, the Makupa creek, tropical diseases, torrential rains, swamps, the infamous man-eaters of Tsavo, drought, overcoming the Rift Valley and attacks from the Nandi and the Kipsigis. In May 1899 the railhead reached Nyrobi (Nairobi), a Maasai word meaning a place of cool waters. Nairobi was serene and unpolluted.

In spite of the problems the railway builders faced, they pushed on and reached Kisumu (Port Florence) on 19th December 1901 having covered a distance of 920km from Mombasa. The Uganda Railway (UR) as it was known then, was build at a cost of 5.5 million pounds and four human lives for every mile among them 5 Europeans. An associated steamer service was established on L. Victoria to transport passengers and goods across the lake to Uganda. In 1907, for example, Winston Churchill, then Under Secretary of State for Colonies, (later Britain`s Prime Minister) travelled on the railway and on a steamer on L. Victoria. These coal- burning steamers also produced a lot of smoke on voyages to Uganda, Sudan and Tanganyika.

slidepngInitially, the British government was unwilling to commit state funding to colonial development but encouraged private chartered companies to do so. As such, the Imperial British East Africa Company (IBEAC), owned by Sir William Mackinnon started to build a light (60cm) gauge railway line from Mombasa into the hinderland of Kenya in 1889. However, only 11km of the Central Africa Railway (CAR) was laid before the project was abandoned.
The first railway locomotives in Kenya were powered by steam engines. Two small 0-4-2 side tank steam locomotives were supplied to the IBEAC for use on the CAR in 1890 by the Kerr Stuart &Co., of Glasgow. These engines emitted hitherto unseen amounts of smoke which led to the locals referring to them as magari ya moshi.
During the construction of the Uganda Railway, Eng. Whitehouse imported bigger secondhand “F” steam locomotives from India. Between 1896 and 1898, 34 new ones were delivered from Britain by Kitson of Leeds, Neilson Reid of Glasgow and the Vulcan Foundry of Lancashire. 36 locos of 2-6-0 wheel arrangement were imported from the US by the Baldwin Locomotive Works of Philadelphia in 1899 and 1900. This became the “B” class of UR.
The “F” class locomotive weighed 30tons and her tender could carry 1,500 gallons of water. The “B” class weight 25 tons and carried the same amount of water as the “F” class. Both the locos were coal burning (imported from South Africa). Wood fuel replaced coal in 1903 as it was less expensive and readily available. However, it produced more smoke than coal. UR administration ensured plantations of eucalyptus and other fast- growing trees were established to provide wood fuel for locomotives. The class B4 road traction steam engines supplied by John Fowler of Leeds were very useful in moving construction gangs ahead of the railhead.

smoky steamyThe most smoky steam locomotive to have operated in Kenya is the 59 or Mt. class articulated Beyer garratt. It remains the most powerful meter-gauge loco ever built. It was designed to solve the problem of very large amounts of freight to be moved after the Second World War on limited line capacity. This loco was introduced in Kenya in 1955 and was retired in 1980 from regular duties. However, it works tourist excursions today. The locomotive weighs 252 tons and is capable of hauling 1,200 tons on a 1.5 gradient. Its articulated chassis allows it to cope with sharp bends.
A steam engine has a steel fire-tube boiler that contains pressurized water and steam. A firebox located on the rear of the boiler has a water filled steel chamber surrounding the flame in the firebox. The heat extracted from the firebox, tubes and smoke in the boiler converts the water to pressurized steam in the boiler. The smoke then enters the smokebox and escapes into the atmosphere through the chimney.  In order to help in pushing out smoke and hot gases, the driver does a blow back. He uses a blower ( a pipe ending in a ring containing pin-sized holes) to create a ring of steam jets which forces out smoke.
The steam is used to drive the locomotive, and operate the whistle, brakes, pumps, air flow etc. Combustion in a steam engine is not very complete leading to a significant amount of smoke and sparks being produced. .

As new sources of energy were discovered e.g petroleum, diesel etc, the steam engine was replaced by more efficient, less maintenance intensive internal combustion engines. The introduction of main line diesel locomotives in Kenya in 1960 spelled the beginning of the end for steam engines. However, it was not until 1980 that diesel locomotives fully took over motive power. But today, Kenya Railways Corporation (KRC) operates tourist excursions using three preserved steam engines. In some mountainous and high altitude rail lines, steam remains in use because it is less affected by reduced air pressure than is diesel.
By 2007, there were 174 serviceable diesel locomotives in Kenya out of which 55 were in operation.
There are three types of diesel-locomotives in Kenya; diesel-mechanical, diesel-electric and diesel- hydraulic. Today almost all diesel locomotives are diesel-electric. The first diesel engine worked the railway soon after Dr. Diesel patented his first compression ignition engine in 1892.

These are the most simple of them. It uses a gearbox mechanism in the same way as road vehicles. However, it has been impossible to build a gearbox which can cope with a power output of more than 400 horsepower without breaking. Therefore this type of transmission is only suitable for low powered shunting locomotives. The first diesel loco in Kenya, 32class was of this type. Because of its manual gearbox transmission, they produced more smoke than other diesel engines of its weight on take-off and when engaging gears.

The diesel-hydraulic locomotive was developed in Germany. It is more efficient than all diesel engines but is mechanically complicated and therefore prone to breakdown. In Kenya it is represented by the 62 class. These engines emit less smoke because they are lighter for the same power output when compared with diesel-electrics. They are therefore ideal for branch lines eg Nakuru-Kisumu. It also has a better starting traction effort relative to its weight.

In a diesel-electric locomotive, the diesel engine drives an electrical generator whose output provides power to traction motors which in turn moves the wheels. In these engines all axles are driven by individual motors and can lose grip thus forcing the driver to exert more traction energy which results in excess smoke production. This occurs on slippery rails and wet gradients. In Kenya, diesel-electric engines are represented by the following classes of locomotives: 87,71,72,92,93 and 94. The 47 class shunter too falls in this category.

Factors Determining the Amount & Kind of Smoke Emmission in Locomotives

  • How heavy the load is
  • The gradient
  • Type of fuel in use- whether coal, firewood or diesel
  • State of traction surface- whether wet or dry
  • Speed. Steam engines were slower attaining a high speed of 90miles an hour. A diesel engine can reach a speed of 125 miles (201km) an hour. In Kenya the maximum speed limit is 72 km/hr.The higher the speed, the less the emission of smoke.
  • Mechanical state of the locomotive- is the fuel combustion complete?

Significance of Locomotive Smoke
Between 1900 and 1960 railways were main contributors of urban smoke in Kenya. This is because there was no major town that was free of railroads.

  • Smoke makes the working environment poor particularly where steam engines are involved eg the footplate, workshops, stations etc. The railway administration had to award cleanliness trophies to clean stations.
  • According to the World Health Organization, wood smoke causes 1.5 million deaths a year- Smoke causes lung cancer, runny eyes and noses, nausea, asthma, chest pains. In 2001, the mortality within the German population was 14,400 people as a result of diesel soot exposure (Source Wikipedia)
  • Sparks accompanying smoke could cause fires to forests, fields and homes. The government later established buffer zones of 30 meters
  •  Sign of an approaching train. In the past when trains ran on time, this would be used to tell time.
  • Smoke shows the mechanical state of the locomotive- whether fuel combustion is complete or not
  • Smoke fouls the air with a dark pall impeding visibility
  • Soils merchandise and clothing
  • Diesel exhaust can deposit onto water, soil and vegetation thus contaminating them
  •  Diesel smoke contributes to global warming because it contains the greenhouse gases methane and carbon dioxide


It is unfortunate that little research has been done to document the effects of railroad pollution in Kenya. The government should commence research into the impact of locomotive air pollution in order to reduce exposure by railway workers to harmful diesel particulates. In his paper titled “Air Pollution Studies: Trends and Challenges in Kenya”, D.M Maina says there is no national programme on air pollution measurements and that the measurements are mainly academic, uncoordinated and “consumerless”.

However, the Environment Management and Coordination Act, 1999 mandated the formation of the National Environmental Management Authority whose main objective is to discourage all forms of environmental pollution. According to Maina, Nairobi has high levels of particulate matter which is higher than the limits set by WHO.