The average front-engined bus in India is just a truck with seats mounted in its back and a roof over them as bus operators just buy truck chassis and build bus bodies on them. These are not just horribly inefficient but also uncomfortable and back-breaking. Almost everywhere in the world buses are always back-engined and operators buy real buses and not trucks. But in India we still ride in trucks masquerading as buses. To attract people back to public transportation, India should immediately move towards making all transportation buses rear-engined, because we deserve better rides!
Advantages of Rear-Engined (RE) buses over Front-Engined (FE) ones
Passengers are much less fatigued after traveling in a rear-engined bus. This is because:
Less (or no) Noise: Engines mounted in the front sit literally in the cabin. As the engine is in no way insulated from the rest of the bust, its entire noise (waves) is propagated into the passenger cabin (along with the heat). RE buses have their engines hidden away in the back with noise insulation and their heat travels outwards.
Less Vibration Inside: FE buses have engines in front and their driving wheels at the back. Engines drive the wheels by the means of a long metal rod which is a driveshaft called a propeller shaft that reaches from the the engine to the wheels (housing). The propeller shaft runs the entire length of the bus and as a result its vibration and that of the engine is transmitted throughout the length of the bus.
Better Efficiency: Much power and acceleration capacity is lost through the entire propeller shaft and its associated transmission business though gear cogs. Also, the engine needs to work much more as it needs to drive both the shaft and the wheels. Rear engines sit almost on top of the wheels and some transmit power and torque directly to the wheels through something called a transaxle. There is a reason why super-sportcars have all mid-mounted engines :)
Space Saving: Rear engines free up space in the front for passengers and allow low floors for city buses while freeing up cavernous storage spaces underneath coach-buses, which in India we so efficiently use to transport motorcycles. This is not possible for FE buses because of the propeller shaft.
Better Performance: Because the engine sits closer to the wheels, there is the obviously better acceleration, top speed and fuel efficiency. Driver fatigue also is substantially reduced because he/she is not exposed to hours of 120 decibel noise, heat and smoke.
Comfort and Safety: Apart from the obvious absence of noise and vibrations, the engine in the back aids ride comfort because it shifts the center of gravity of the bus backwards and downwards which also gives better stability to the bus and also prevents passengers from being thrown about every time the bus goes around a curve. The weight of the engine counteracts the "jump" passengers at the back experience when the bus goes over a road hump or pothole.
When will we finally quit living in the 1970s and catch up with the rest of the world? Tata and Ashok Leyland should seriously step up their efforts to come out with winnable mass-market rear-engined buses for the Indian market. (Tata's Marcopolos are a disaster). Now you know why Volvo came out of nowhere and is today close to becoming market leader in India, and why the name "Volvo" has become synonymous with the ultimate in luxury travel in India.