Locomotive Boiler: Parts, Working, Advantages, disadvantages, Applications

Today I am going to discuss the locomotive boiler. 

If you are here to know the detailed knowledge about this boiler, then you landed in the right place.

So, grab your seat and feel comfortable while I start the engine of this knowledgeable journey with Engineers Rail.

Wait.. It would be nice to have this whole article as a locomotive boiler pdf, then it would be easy for you to find offline when you needed. Feel free to download this whole article as a pdf at the end of the article.

So, Let’s get started…

Locomotive Boiler-

A locomotive boiler is a firetube, horizontal, Multi tubular, internally fired boiler.

It is basically used in railway locomotive engines and marines.

Parts & Construction of Locomotive Boiler-

Here are some locomotive boiler mountings and accessories and their working-

  1. Boiler Shell
  2. Grate
  3. Ashpit
  4. Deflector
  5. Water level indicator
  6. Pressure gauge
  7. Safety Valve
  8. Manhole
  9. Superheater
  10. Smokebox
  11. Steam Dome

1. Boiler Shell-

it is the other parts of the boiler consist of tubes inside knowns as fire tubes, surrounded by water.

2. Grate-

The grate is basically made of cast iron rode spacing each other to place the solid fuel and burn.

3. Ashpit-

Ashpit is used to collect the ashes coming from the grate through burning solid fuel.

4. Deflector-

This device is used to deflect hot gases generated by burning fuel.

5. Water level indicator-

A water level indicator is used to check the water level of the boiler where one vein of the indicator is connected to the steam dome and while the other is connected to a water pump.

6. Pressure gauge-

This device is used to measure the pressure of the steam.

7. Safety Valve-

The safety valve is used to maintain the needed pressure of the boiler, if it goes beyond the needed pressure, the safety valve will release those extra pressure to save the boiler or any accident just like a pressure cooker.

8. Man hole-

This manhole is used to clean the boiler from inside.

09. Superheater-

As you know, a superheater is used to convert saturated steam into superheated steam.

10. Smokebox-

The smokebox is used to collect the smoke coming from the fire tubes by burning fuel, released in the environment with help of a blower through the chimney.

11. Steam Dome-

A steam dome is used to regulate the steam produced by the heat exchange between the hot gas and water inside the boiler shell.

Diagram of Locomotive boiler-


Working of Locomotive Boiler-

When we burn solid fuel like coal and this cause to generate hot gases due to heat generation.

Now, these hot gases move inside the fire tubes with the help of a deflector which deflects the hot gases inside the tube.

When hot gases enter into fire tubes, this cause to hot the tubes also, as is obvious.

These hot tubes are caused to heat up the water flowing outside of the tubes.

As the water temperature rises to the boiling point, these phenomena cause the generation of saturated steam.

Now, this saturated steam sends to the steam dome located top inside the boiler shell.

Now, This saturated steam is now sent to the superheater from the steam dome, to superheat the steam.

And, finally this superheated is send to piston reader to use.

This is how this boiler works.

Advantages of Locomotive boiler-

  1. Portable
  2. Quick Start
  3. Economical
  4. High steam generation capacity
  5. Compact
  6. Easy operation
  7. Easy transportation


  1. Corrosion and scale formation
  2. Overheating Issues
  3. Difficult to clean sometimes


  1. Railways
  2. Marines
  3. Traction Engines
  4. Steam rollers
  5. steam engines

For more information, it is recommended to watch out this animated video-



This is it for now. I hope you liked the to-the-point explanation of the Locomotive Boiler. 

If so, consider sharing with your friends and colleagues to help spread good knowledge out to needy ones.



Here are some more of the recommended Articles to read, Consider reading further-

Thank you for being with me. I hope to see you in the next session.



Here is your locomotive boiler pdf, which I promise to give at the end of the article. So, here it is-

locomotive boiler pdf



Before you go, here are some Q&A sessions on this boiler-


Is the locomotive boiler externally fired?

No, this is an internally fired boiler.

What is the difference between externally fired and internally fired boilers?

The basic difference between externally and internally fired boilers is the placement of the combustion chamber. If the combustion chamber is placed inside the boiler shell, known as internally fired boiler and If outside the boiler chamber, known as externally fired boiler.

Which safety device is used to protect the boiler when the water level falls below a minimum level?

A. Water level indicator
B. Fussible plug
C. Blow off cock
D. Safety valve
Answer- B. Fussible plug

Fusible plug for a steam boiler is an alloy consisting of bismuth, lead and-

A. Tin
B. Copper
C. Aluminium
D. Zinc
Answer- A. Tin

In a boiler, the feed check valve is used for-

A. Control the feedwater flow rate
B. Check the water level in the drum
C. Ensure unidirectional feed flow to the drum
D. None of these
Answer- A. Control the feed water flow rate

The type of locomotive boiler is-

A. Multi-tubular
B. Horizontal
C. Internally fired
D. All of these
Answer- D. All of these

The fusible plug in small boilers is located-

A. In the drum
B. In the fire tube
C. Above the steam dome
D. Over the combustion chamber
Answer- D. Over the combustion chamber

The general energy equation for system boiler is given by-

A. Q= H1-H2
B. Q= H2+H1
C. H1-H2+ work done
D. H2-H1+ KE
Answer- D. H2-H1+ KE

Heat is transferred by conduction, convection & radiation in-

A. Boiler furnace
B. Melting of ice
C. Condensation of steam in the condenser
D. None of these
Answer- A. Boiler furnace

Equivalent evaporation is the amount of water evaporated in a boiler from and at-

A. 0C
B. 100C
C. Saturation temperature at a given pressure
D. Room temperature
Answer- B. 100C

Match List=I(Name of boiler) with List-II(Features)-
A. Lancashire
B. Cornish
C. La-mount
D. Cochran
i. High pressure water tube
ii. Horizontal double fire tube
iii. Vertical multiple fire tube
iv. Horizontal single fire tube

Answer- A-ii, B-iv, C-i, D-iii

Which one of the following is not an accessory for the boiler?
A. Condenser
B. Economizer
C. Air-preheater
D. Feed water pump

Answer- A. Condenser

In a boiler, the air preheater is invariably located between-
A. Forced draft fan & chimney
B. Forced draft fan & furnace
C. Economizer & feed pump
D. Condenser & feed pump

Answer- B. Forced draft fan & furnace

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