Railway Accounts Department Examinations

Showing posts with label Specific Energy Consumption. Show all posts
Showing posts with label Specific Energy Consumption. Show all posts

Monday, January 31, 2022

SFC - Specific Fuel Consumption and SEC - Specific Energy Consumption


SFC - Specific Fuel Consumption

  • Indicator of Fuel economy

  • Measured in terms of Tonne KMs 


  • Definition: Amount of fuel consumed per unit of work done. 

  • Measured both for the Engine and the Total formation of the Train. 


  • Lower the SFC, the Better the Fuel Economy. 




  • The  unit of  SFC  for  Engine is Grams/bhp hour.  Grams represent Quantity of Fuel, whereas bhp hour (brake horsepower) represents work done. . 

  • At present, the SFC of ALCO Engine is 155 Grams and of GM Engine 150 Grams (Approx.)  


  • ALCO stands for American Locomotive Company


  • GM stands for General Motors 


  • For  the locomotive, the SFC  of  the engine  can  be  calculated by  measuring time  to  calculate the  Horse  Power  output in  terms  of  BHP.Hr  for a  specific  amount  of  fuel  consumption while the  engine  is  put  on load  during  load  box  test. 

  •  This  is  more  accurate  in  order  to  calculate  engine  efficiency,  because  output  of  the  engine is  measured  at  the  crankshaft,  neglecting  all  other  losses  of  the  locomotive.   


  • There  is  a  second  method  of  calculating  SFC,  in  which  the  amount  of  work  done  is measured  in  terms  of  Tonne  Km.  This  is  more  practical  because  here  the  total  losses incurred  in  the  locomotive/  formation  of  train  are  taken  into  consideration  for  calculating the  SFC.  

  • The  unit  used  is  in  liters/  1000  GTKM.  (GTKM  means  KM  earned  with  the gross  tonnage  hauled  including  the  weight  of  the  locomotive). 

  • As  train  resistance,  air  resistance  and  other  parasitic  loads  of  locomotive/  train  varies  at different  speed  ranges,  so  SFC  of  the  locomotive  is  calculated  with  respect  to  its  service. 


  • Calculated per 1000 GTKMs 

  • SFC =  HSD oil in Liters / 1000 GTKMs 

  • HSD Liters represent Quantity of Fuel, whereas 1000 GTKM  represent work done. 

  • HSD stands for High-Speed Diesel

  • GTKMs -Gross Tonne KMs -  KMs earned with the Gross Tonnage hauled (incl: of Weight of Locomotive & Rolling Stock ) 


  • NTKMs - KMs earned with the Net tonnage hauled (excl: Weight of Locomotive & Rolling Stock)  


  • Indian Railways -SFC (Approx)


2.50 Liters per 1000 GTKMs


4 Liters per 1000 GTKMs

  • SCR - 2017-18- SFC


1.52 Liters per 1000 GTKMs


2.81 Liters per 1000 GTKMs


  • SFC for Shunting services - not calculated 


SEC - Specific Energy Consumption  

  • For Traction - SEC - Specific Energy Consumption = Used KWH  / 1000 GTKMs  


  • Amount of Electricity (in KWH - Kilowatt hours) consumed per unit work (1000 GTKMs done 


  • Engine: The amount of electricity (in KWH - Kilowatt-Hour) consumed per unit work done. 


  • Over the last few years, Railways have been able to improve upon Specific Energy Consumption (SEC) by about 19% through various energy conservation initiatives. 


  • For electric locomotives,  there are mainly  3  modes of service for which  GTKM  earning is recorded to calculate  SFC.   

The  figures  of  SECs (Approx),  accordingly  are: 

  • SEC-EMU     = 40  KWH./  1000  GTKM 

  • SEC-Pass        =  20 KWH./  1000  GTKM

  •  SEC-Goods    =  8   KWH/  1000  GTKM 

  • The  figures  represented  by  electrical  department  is  entirely rhetoric.  Because for  EMUs for recording energy consumption the energy meter is not available with the  locomotive and the figures are purely based on assumption.   

  • For passenger and goods service locomotives,  although an energy meter is available figures are manipulated.  


  • For locomotives in shunting service  GTKM  earning can’t be recorded,  hence it is not calculated.   


  • Both SFC and SEC units are used in the Fuel budgeting of Diesel and Traction.  

Factors that affect SFC

  1. Engineless loaded 

  2. Weak Engine 

  3. Other factors P.Way, Signaling, Operating facilities

  4. Vehicle Design 

  5. Driving techniques

Steps were taken to bring fuel efficiency 

  1. Arresting any leakages. 

  2. Application of Fuel Kit

  3. High performance & high capacity turbo supercharger

  4. Improved Air Cooler  

  5. Improved Piston and Piston ring 

  6. Use of Multigrade oil 

  7. Minimum inventory in RCDs - From 15 days to 5 days  

  8. Use of B-5 blended HSD - 5 % Bio Diesel  

  9. Fuel pattern - Cheaper RCDs are fuelling more to Diesel Locomotives to avoid fuelling at costlier RCDs  

  10.  Withdrawn overaged WDMs Locomotives from mainline services 

  11.  DPC - Driving Power Car of DEMU train  -  Conversion to dual-fuel i.e., Diesel + CNG 

  12.  Auxiliary Power Unit - introduced in Diesel Locomotives - for automatic shutting down of Diesel Locomotives while standing idle.  

  13. CReDI - Common Rail electronic Direct Injection - Developed & Fitted in Diesel Locomotives  

  14.  Developing alternative fuel systems like Traction, Solar Power to reduce the consumption of Diesel. 

  15. IROAF - Indian Railways Organization of Alternate Fuels, Chennai - Developing the alternative fuel.  

  16. The performance of Loco Pilots is being monitored regularly. 

  17.  Monitoring of idling of Locomotives has been started through REMMLOT - Remote Monitoring and Management of Locomotive and Trains fitted in Locomotives. 

  18.  All overaged Broad Guage Diesel Mixed Traffic Engines (WDM2) locomotives have been withdrawn from mainline service. 

  19.  Retro-fitment of Microprocessor control system in diesel Locomotives have been executed to achieve fuel efficiency.

  20. Miller cycle-based turbochargers and Variable Turbine Geometry (VTG) Turbochargers have been developed for ALCo locomotives to achieve fuel efficiency.

Solar Energy

  •  Indian railways have planned for 1000 MW of solar power plants by 2020-21 with 500 MW at railway rooftops for non-traction use and 500 MW land-based for mostly in traction use. 

  • The solar power from land-based plants shall be mostly used in train operations.

  •  IROAF is implementing the provision of Solar Panels on the rooftop of coaches and Brake Vans of freight trains for taking up part of hotel load (electric lighting and fans load).

  •  In Goods train, Solar Panels on a trial basis have been fitted on the rooftop of 50 Nos. Guard Brake Vans.

  •  In passenger Trains, Solar panels on a trial basis have been fitted on the rooftop of 06 Nos. Trailer Coaches of Diesel Electric Multiple Units (DEMU).