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| Rail Bus leaving Gelioya on the way to Kandy. |
Sri Lanka is a country with a great history which runs deep into the dark ages. Along that time line, she had been very fortunate create a civilization that excelled in hydraulic engineering and construction engineering which, after thousands of years stand to amaze the present generation world-wide. Sri Lankans still continues to be innovative in all the fields they associate themselves.
One such innovative spirit was Mr. P. P. Wijesekara, who saw the long-lasting problem in the Sri Lankan Railway: the unavailability of a suitable mode of transport which cater to the routes with low passenger density while not compromising factors such as economy and not hampering the running of other trains. This was made it into an opportunity to bring out to the world, the concept of a Rail bus.
The background for this innovation, according to Mr. Wijesekara was that by the early 1990’s, fast express passenger trains had been called to stop at intermediate stations and sometimes, even the rail halts. This adds a significant delay to the overall running time of these trains, making it an arduous chore for the long-distance traveler.
Also, a 300-ton train travelling at around 60 kilometers per hour has a lot of momentum, therefore slowing and stopping it involves a lot of disadvantages. That is a loss which cannot be made up, or even approached. Then again there was the fuel expense of restarting from that stop as well. This became a major issue on the North line, where a lot of stations were situated along graded tracks even though, they aren’t heavy as in the Up-Country Line, they run for longer a distance.
Working a small Diesel Multiple Unit solves many of these setbacks but, a DMU has a powerful diesel motor, which is designed to power a train hauling a train full of passengers with good acceleration and speed. Additionally, the passenger capacity of the DMU is much higher than what is available on these routes.
Another problem was that there are some isolated stations in Sri Lanka, that barely had any road access, and the railway was the only mode of transport. Though there was no heavy traffic, almost everyone uses whatever available train to fulfill their transportation needs. These were required to be stopped at way side halts and provide easy and quick boarding, mostly without a platform.
The solution for these problems was a vehicle with a low frame (so that anyone can board without a platform), which is light enough (so that it won’t require a powerful diesel motor), fuel efficient with a good acceleration, easily serviceable, cost efficient and safe.
To cater to these specifications, the SLR under the guidance of Mr. Wijesekara, then Chief Mechanical Engineer at Ratmalane Workshops decided to take a road bus, and converted it to run on the rails. With a 180hp diesel engine, and a mere 2-ton weight, it was a far more powerful machine, with good acceleration and fuel efficiency which was unobtainable with a traditional rail car unit.
Initial drafts were made in the early 1990’s, after which many battles were fought with the authorities for approval. The first bus made its debut on 18th of July, 1995 and made its first ever trial run to Polgahawela and back.
This initial unit was based on a TATA Dimo bus with a mechanical transmission, with wheels and axles replaced with rail wheels, and a few other modifications to the drive train. A further unit of the same make was coupled back to back with the original bus, making it a mini DMU, with their own diesel engines.
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| Original Rail Bus unit. (Photographer unknown) |
This rail bus was not designed overnight and the team had to fight many technical difficulties as well as other difficulties in order to get it off the ground. Some such technical difficulties included a safe braking system, which must be able to control both the buses from any unit, a safe coupling system to enable riding along a graded track without becoming uncoupled, and modifications to the bodywork as well.
Wheels were taken off old coaches, with custom made axles with driving mechanisms and as the latest development, a 4 wheeled bogey had been incorporated to reduce sway and jerk experienced on the run.
This rail bus had been in service for almost all over the island, including the heavily graded up country main line. Due to the low weight and relatively powerful diesel motor, it is capable of hauling two buses with only one engine running. Long distance trains could be worked as express trains among major stations, with the rail bus feeding the crowd from intermediate stations.
It had been noted that in some areas, passengers were very careful about this rail bus unit that they protected and cared for it is their own vehicle. Especially along the Mahawa- Kurunegala stretch where a daily rail bus service was operated to cater to the rural villages along the track.
Rail bus concept was unique to Sri Lanka, and was truly a Sri Lankan innovation. Today, there are over 26 units of converted buses, mostly made in India by Ashok Leyland. Their body work is designed specifically in India and other modifications are done in Sri Lanka according to the local needs.
Railways, or to that matter any and everything in life brings up problems and challenges. Facing them at times is difficult but, if you can treat the problem as an opportunity, and fight the odds, you can ultimately come out with brilliant innovations, to serve the whole nation. The rail bus might become obsolete one day, but that will not devalue it in any amount. We, the present generation is very fortunate that we are able to ride on these purely Sri Lankan innovations, thanks to the ingenuity of the masterminds in Sri Lanka
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| Rail bus unit at Peradeniya Junction Old Platform |
P.S-
I am much thankful to my colleague Bryan Senaratne for editing this article.
