BEIJING - Beijing will install protective screens for the city's two oldest subway lines in a bid to enhance safety at boarding platforms, said municipal authorities on Wednesday.

The lack of protection against bare train tracks exposes passengers to safety hazards on the two lines, called line 1 and line 2, and a man was killed on Monday after he jumped onto the track at a line 2 station and was hit by a train.

Subway line 1 runs through the city center from east to west and line 2 runs a loop line in the downtown. The city currently?has 17 subway lines.

It has so far completed construction of protection screens on newer lines that connect with line 1 and line 2, the Beijing Municipal Commission of Transport said.

However, installing protective shields for the capital's oldest two lines will be a much more difficult task, the commission added.

Once installed, these screens must be subject to 5,000 repeated tests before being put to use. They should also be adjusted with existing technical systems in the subway.

Construction will last no more than four hours each day when the two lines are not in operation. The first train departs shortly after 5 am and the last leaves before 11 pm on the two lines.