The Railways' ambitious plans to bump up the speed of the historic Kalka Shimla toy train to cut the journey time by two hours has been put on the backburner, sources said.

According to them, steep curves, gradients and lack of lateral space are making it technically impossible to make the toy train run any faster.

At the request of the Himachal Pradesh government, the railways has over the last two years conducted studies if the toy train can be run at an increased speed.

In 2018, the Northern Railway got the Research Designs and Standards Organisation (RDSO) to assess if the speed of the Kalka-Shimla toy train could be increased.

"It is a very difficult project. The curvature is more and the efforts to straighten it have failed due to a lack of lateral space. It is not technically feasible. A final decision is yet to be taken after the RDSO study is completed. However, it seems unlikely that the speed of the toy train can be increased beyond a point," said an official.

One of the reasons for this is that the cost incurred to make the changes suitable for a faster running toy train does not justify the gain in speed of barely 3 to 4 km per hour.

However, an official reply from the Railways on the status of the project is awaited.

"As of now, the project is on the backburner," a source said.

Officials also highlight the limitations presented by the terrain, with 62 landslips being experienced in this calendar year itself. Around 90 per cent of the track is full of curvatures with the sharpest being 24 degrees, sources said.

"It is because of the slow speed (of the train) that no mishap has happened on the route," an official said.

At present, the speed of the train is 22-25 kmph and the plan is to increase it to 30-35 kmph. The slow-moving toy train on a narrow-gauge rail route was awarded Unesco's world heritage site status 10 years ago.

However, in good news for those wanting to make the journey in the future, the British-era coaches will be replaced by swanky ones in the next 10 months.

Rail Coach Factory in Punjab's Kapurthala is in the process of manufacturing around 30 coaches which will be on the tracks late next year, sources said.

"The process will be time-consuming as they will have to undergo two trials. First will be with only the shell and bogie to test them for structural stability and then when it gets approved, a final trial will be initiated," an official said.

The plan, sources said is that these new coaches will be based on LHB technology with stainless steel. Lightweight shells are being designed with large windows and a glass vista dome on the roof.

The Kalka-Shimla route boasts of toy trains like the Kalka-Shimla passenger, Shivalik Express, Kalka-Shimla Express, Himalayan Queen and Rail Motor. Around 20 stations are covered on this route and the trains navigate through around 900 curves.

There are three other narrow-gauge routes where toy trains run are in Darjeeling, Pathankot and Ooty.