The sleeper version of the Vande Bharat Express train, which has become a centre of attraction among railway passengers, will be designed to travel at a speed of 220 km per hour, officials said on Thursday.

These aluminum-made sleeper version trains, however, will run at a speed of 200 km per hour on the tracks, they said.

The chair car Vande Bharat Express trains will be replaced by Shatabdi Express in a phased manner, while the sleeper version is going to be an alternative to Rajdhani Express trains, they said.

The Railways has issued a tender for 400 Vande Bharat trains and the work will be approved by the end of this month, they said.

Some of an initial lot of such trains could also be sleeper versions of the indigenously made trains, according to officials.

Four major domestic and foreign companies have come forward for the production, officials said.

According to the plan, the first 200 Vande Bharat trains will have seating arrangement on the lines of Shatabdi Express and will be designed to travel at a speed of 180 km per hour.

But considering the inadequate safety and security of railway tracks, their speed will be restricted to 130 km per hour. These trains will be made of steel, officials said.

In the second phase, 200 Vande Bharat trains will be sleepers and they will be made of aluminium.

"The second version of the sleeper Vande Bharat trains will run at a maximum speed of 200 km per hour. For this, the tracks of Delhi-Mumbai, Delhi-Kolkata railways are being repaired, signal system, bridges are being fixed, and fencing work is going on," an official said.

"Apart from this, anti-collision technical armour is being installed on both the railway routes at a cost of Rs 1,800 crore," the official said.

Four hundred trains will be produced at ICF at Chennai in Tamil Nadu, Latur Rail Factory in Maharashtra and Sonepat in Haryana in the next two years, officials said.