THE EVOLUTION OF LOCOMOTIVES IN SRI LANKA

Are you an enthusiast about trains and locomotives? It’s doesn’t matter whether you are zealous or not, most of us have to use train as our transportation mode. The railway network is spread over considerable terrain in Sri Lanka.

Figure : Railway network(www.Railway.gov.lk)

 With the extension of coastal line from Mathara to Beliatta total length railway network Is close to 1600km now. [1]

Train locomotives have served as the backbone of railway. Since the inaugural train dispatched from Colombo to Ambeypussa in 1864 large number of locomotives have been used to the date. They have been classified into several classes according to the type of locomotive. But majorly only two types of locomotives can be categorized with respect to the power source.

1.    Steam locomotives

2.    Diesel locomotives

STEAM LOCOMOTIVES

At the infant age of Sri Lanka railway (Ceylon Government railway(CGR)) steam locomotives were used. Most of them were imported from the United Kingdom. Even though Diesel engines were introduced in 1950 steam locomotives had been the heart of railway until 1970.Over 400 steam locomotives were imported within that period. They have been categorized under class A, B, C, D, E, F, J, H, K, L, V and R.

Steam Engines are external combustion engines where the fluid is separated from the combustion products. As coal was abundant and cheap fuel in that era, steam locomotives were highly utilized. But the environmental pollution due to coal was significantly high. They were subsequently replaced by the diesel locomotives. As a consequence of this, diesel locomotives were imported to Sri Lanka after 1940. [2]

DIESEL LOCOMOTIVES

When consider the diesel locomotives, there are two identifications. They are diesel locomotive engines and Diesel Multiple Unit(DMU). The uniqueness of DMU is that it is designed as one unit which train is powered by on-board engines and engines are incorporated into carriages, wherefore no separate engine is required.

 Class s12 DMU  

                                      

  Class M locomotives

                          

These diesel locomotives can be categorized in to three main types according to power transmission method.

1.    Diesel Electrical Locomotives

2.    Diesel Hydraulic Locomotives

3.    Diesel Mechanical Locomotives

Diesel Electrical Locomotives

Majority of diesel locomotives which are currently used in Sri Lanka are electrical. Class M locomotives and class S DMU after S8 have this transmission method. Main parts of this as follows.

   Figure : Parts of Diesel electric Locomotives 

 Figure : Simple chart of parts of Diesel electric locomotives

      

v Fuel tank -Store diesel

v Diesel engine

v Prime mover

v Radiator

v Alternator (those who have DC motors)

v Air compressor

v rectifier

v Inverter

v Traction motors

Figure: A Traction motor

 Figure : Types of axel  

  Figure : Lighting control system of DMU

    

First the diesel is injected from fuel tank to engine. Diesel engines work by compressing air. This increases the air temperature inside the cylinder to such a high degree that atomized diesel fuel injected into the combustion chamber ignites spontaneously. The crankshaft connected to engine is linked to a generator or alternator. It converts kinetic energy into electric energy while generating AC current and it goes through a rectifier, in order to convert AC current into DC current. The electric locomotives which have DC motors can directly use converted DC current. But modern locomotives require three phase AC Current as they consist of some AC motors. Therefore, inverter is required for that process. The axle of traction motors are connected to axle of the bogies. Diver can change both direction and speed of locomotive by changing the current. An air blower is located to cool down the traction motors. It also helps to cool down the alternator when applying the dynamic brakes to slow down the train. There are both pros and cons in these models.

v  Easy to maintain

v  Low wearing, tearing

v  Less lubrication

v  Smoothness in transmission

Are the main advantages

v  Less acceleration efficiency than other models

v  Power loss is higher than diesel hydraulic locos.

Are significant dis-advantages.

DIESEL ELECTRIC LOCOMOTIVES

1)      Class M1

v  Built in Britain

v  Imported in 1952

v  Engine type - mirlees JS12VT

v  Power output-1000hp

v  Axel arrangement-A1A-A1A

v  Weight-88tons

v  Total Imported- 25 [3]

2)      Class M2

v  Manufactured in Canada

v  Imported       -1954-1956

v  Sub classes      -M2,M2a,M2b,M2c.M2d

v  Power output    -1425hp and 1310hp(M2d)

v  Axel arrangement -A1A and Bo-Bo(M2c)

v  Weight 79 tons

v  Maximum speed -112kmph

Total imported -14 (1 was blasted by a bomb, another one was damaged by tsunami but now repaired and currently 13 in service) [3]

3)      Class M3

v  Built in Sri lanka-1956

v  Used the parts of S1 DMU

v   Power output 180hp

v  Maximum speed 89kmph

v  Axel -Bo-Bo

v  Weight -47 tons

v  Total produced -2 [3]

4)Class M4

v  Manufactured in Canada; imported in 1975

v  Engine type -Alco bombardier 251-c3- 4stroke 12Cylinders

v  Power output 1750 hp

v  Maximum speed-65kmph

v  Axel arrangement -Co-Co

v  Total imported -14 [3]

5)Class M5

v  Built in Japan

v  Built by Hitachi 

v  Imported in 1970

v  Sub classes -M5A ,M5B

v  Engine type -V12 diesel engine

v  Power Output-1640 hp (M5A and M5B-1150hp,M5B-1600 hp)

v  Maximum speed -97kmph

v  Axel arrangement -B0-Bo

v  Weight - 60-70tons

v  Total imported -16 [3]

6)Class M6

v  Built in Germany

v  Imported in 1979

v  Engine type -V12 two stroke diesel

v  Power output-1650 hp

v  Maximum speed -90kmph

v  Axel arrangement A1A-A1A

v  Weight-60-70tons

v  Total imported -16 [3]

7)Class M7

v  Built in Britain

v  Imported in 1981

v  Engine type -V8 two Strokes

v  Power output-994hp

v  Weight -66tons

v  Maximum speed -80kmph

v  Axel Arrangement -Bo-Bo

v  Total imported- 16 [3]

8)Class M8

v  Built in India

v  Sub classes -M8A

v  Imported in 1996 and 2001(m8a)

v  Engine type -M8(V16) ,M8A(V12)

v  Power output- 2800hp(M8)  ,2200hp(M8A)

v  Maximum speed- 120kmph

v  Axel arrangements -Co-Co

v  Weight -112 tons

v  Total imported -10 [3]

9)Class M9

v  Built in France

v  Imported in 2000

v  Engine type -V12 4 stroke

v  Power output -3200 hp

v  Maximum speed-110kmph

v  Axel arrangement -C0-C0

v  Weight -100 tons

v  Total imported- 10 [3]

10)Class M10

v  Built in India

v  Sub classes - M10A

v  Imported in 2012

v  Engine type- V12 four strokes

v  Power output -2300hp

v  Maximum speed -120kmph

v  Axel arrangement - Co-Co

v  Weight- 117tons

v  Total imported -9 [3]

11)Class M11

v  Built in India

v  Imported in in 2018-19

v  Engine type -EMD 12-710G 3C

v  Power output -3000hp

v  Maximum speed -120kmph

v  Axel arrangement- Co-Co

v  Weight -130tons

v  Total imported -10 [3]

DIESEL ELECTRIC DMUS

1. Class S9

v  Built in China

v  Imported in 2000.

v  Engine Type -V12

v  Power output -1580hp

v  Maximum speed -100kmph

v  Weight -73 tons

v  Axel Arrangement -B-B

v  Total imported -15sets [3]

2. Class S10

v  Built in China

v  Imported in 2008

v  Engine type MTU V12 4000R41

v  Power output-1950hp

v  Maximum speed 100kmph

v  Axel arrangement -Bo-Bo

v  Weight- 76tons

v  Total imported -15sets [3]

3. Class S11

v  Built in India

v  Imported in 2011

v  Engine type -KTA50L V16-EFI

v  Power output -1350-1800 hp

v  Maximum speed-110kmph

v  Axel arrangement -Bo-Bo

v  Weight- 100tons

v  Total imported-20sets [3]

4. Class S12

v   Built in China

v  Imported in 2012

v  Engine type -MTU V12 4000R1

v  Power output -1950hp

v  Maximum speed-100kmph

v  Axel arrangement -Bo-Bo

v  Weight- 76tons

v  Total imported-13sets [3]

5. Class S13

v  Built in India

v  Imported in 2018-19

v  Power output -1800hp

v  Maximum speed-120kmph

v  Axel arrangement -Bo-Bo

v  Weight- 76tons

v  Total imported - 5sets [3]

6.Class S14

v  Built in China

v  Imported in 2019

v  Power output -1950hp

v  Maximum speed-120kmph

v  Axel arrangement -Bo-Bo

v  Weight- 74tons

v  Total imported-4sets [3]

7.Class S14a

Imported to carry garbage from Colombo to Aruwakkaru.

DIESEL HYDRAULIC LOCOMOTIVES

There are only few diesel hydraulic locomotives in Sri Lanka. Class W and Class S1 to S8 DMU locomotives have this type transmission method. 

Figure: Parts & Flowchart of Diesel Hydraulic locomotives(http://ceylonrailway.com/technical-info)

The main parts are as follows.

v Fuel tank

v Diesel engine

v Radiator

v Torque converter

v Gear Box.

       

Usually RPM value of locomotive engines is lower than car engines. Accordingly, today the engine RPM varies from 60-100 RPM for large capacity engines to 20,000 RPM for racing car engines. The power to weight ratio in kg/kW varies from 0.4 to 55 kg/kW for slow speed engines. [4] If typical car engine gear system is applied, about 10-15 gears are required to operate a train. Therefore, typical car engines’ gear system is not applicable for locomotive engines. In order to solve this problem Torque converter is applied as a unique component. But when the torque is increased speed get decreased. As a solution, this type of locomotives uses higher RPM than other types and it is around 1500.Torque converter serves a vital component in the processes of engine.

As electric engine, diesel is injected to combustion chamber from fuel tank. During combustion, drive shaft begins to rotate. This shaft is connected to Gear box through Torque converter which is a modified fluid coupling system. This fluid couple consist of two components. [5]

Figure: Hydraulic torque converter (www.railmotorsociety.org.)

1.    An impeller or a pump connect to the engine and it rotates with the engine.

2.    A turbine connected to the gear box.

These two consist of two rotors which are placed close to each other and the space between fans is filled with special oil. When the engine rotates impeller also get rotated. But it’s not possible to transfer more power in this method because torque doesn’t rise over certain value and therefore output power is restricted. But a special component in torque converter which is called “stator” rectifies this error. stator is located between turbine and impeller ad main task of it is to change the direction of oil after hitting the turbine. In this process stator increases the torque while it is keeping stationarity. As a result the power output is increased. Usually there are two torque converters in diesel hydraulic locomotives. Then the resultant power is transmitted to gear box. The throttle of this locomotive has 8 notches. When the driver changes the notch gearbox work accordingly and rotates the wheel of locomotive with required power.

Figure: Control in a locomotive

                                

The dynamic breaks of these locomotives are also called as hydrodynamic brakes. The resistive force for the wheels is produced by the breaking energy heating the hydraulic fluid.

ADVANTAGES

v  Higher acceleration

v  Higher power efficiency

v  Less wheel slips

v  Possible to drive in the flooded conditions

DISADVANTAGES

v  Higher maintain cost

v  Wearing of parts is higher

v  Availability of spare parts is low

Diesel Hydraulic Locomotive Engines

1) Class W Engines

About 45 of Class w1 engines were imported in 1968 from Germany. And after serving about 20 years they were retired due to high wearing and less availability of spare parts.

In 1970 Class w2 Engines were imported and most of them are out of service now.

A new locomotive was built in Sri Lanka using the parts of w1 locomotives in 1977.and they were categorized as Class w3. Most of them are still in service.

Class w locomotives

                     

2) DMUs

Class s locomotives up to S8 is categorized in this group. But now only S8 DMU is in service.

Class S6

Class S7 

      

Class S5

  

    Class S8

v  Built in Japan (Hitachi +Hyundai (South Kore))

v  Imported in 1989

v  Engine type -MTU V12

v  Maximum Speed -88kmph

v  Axel arrangement - B-B

v  Weight -70 tons

v  Total imported -20 sets

DIESEL MECHANICAL LOCOMOTIVES

This transmission system is not used for high power locomotives. This transmission is used for small engines such as shunting locomotives. The main reason for them not being used in heavy locomotives is if the power supplied from the engine is directly connected to gear box, both engine and gear box can be severely damaged due to the large inertial force. Like other transmission methods, fuel combustion in chamber powers the shaft connected to gear box. This is done through a fluid coupling method which act as a hydraulic clutch. Then the mechanical energy output from the gear box is used to rotate the wheels. The power transmitted is quite smaller than other locomotives as they are in the range of 300 to 500 horsepower while on other locomotives it is in the range of 1000-3000.

                   

A shunter (class G and Y)

                         

FUTURE OF SRI LANKA RAILWAY AND LOCOMOTIVES

After initiating the railway service in 1864, gradually it has passed several milestones on the way. But we are still quite behind in railway technology and facilities compared to many developed countries. As young blooming engineers our prime task is to develop these technologies and facilities in order to make these transportation modes more upgraded. [6]

                                              

                                                       

S.G.S.S DE JAYATHUNGA

UNIVERTSITY OF SRI JAYAWARDENAPURA

DEPARTMENT OF CIVIL ENGINEERING

References

[1]	"Railway Network in Sri Lanka," February 2014. [Online]. Available: http://www.srilankatravelnotes.com. [Accessed 12 April 2020].
[2]	"Types of locomotives," May 2018. [Online]. Available: http://ceylonrailway.com. [Accessed 12 April 2020].
[3]	SLRF Staff, "Class M2 - Sri Lanka Railway Forum," 22 September 2019. [Online]. Available: https://slrailwayforum.com. [Accessed 12 April 2020].
[4]	S. D. Mane, "Technologies adopted in Diesel Locomotive Engines over Indian Railways," January 2016. [Online]. Available: https://www.researchgate.net. [Accessed 17 April 2020].
[5]	"The Hydraulic Torque Converter," [Online]. Available: http://www.railmotorsociety.. [Accessed 12 April 2020].
[6]	S. A. Jayasekera, "Megapolis Development Ministry's Light Railway System JICA to provide US$ 1.7 billion," Mirror Citizen, vol. 7, no. 3, p. 573, 2018.