At each end of the city’s suburban platforms stand the Railways’ iconic yellow boards, proclaiming in bold black letters the station’s name. However, below the names, in small, easily missed fine print, is more information — the distance from sea level for that location. Railway officials say the detail dates back to the construction of the earliest railway stations in the city in the early 20th century, when knowing the mean sea level had multiple uses.
The figure written on the boards is the average level of the surface of the sea. “It is the level from which the vertical height of any structure is measured. In Railways, it is important as it decides the height level of the surface on which tracks are to be laid. If they are too low, they will be prone to flooding during monsoon, floods and high tides,” says Rajendra Aklekar, railway historian.
Aklekar adds that earlier, this level would be calculated over a period of time, observing high and low tides. Railway officials say technology has made calculating the distance from mean sea level easier. But earlier, the sea level calculated for railway stations was also used for other civil structures.
“Earlier, most railway stations were centrally located in cities. For construction of other civil engineering structures in the vicinity, the same average as calculated for the railway stations and displayed on the board was used,” says chief public relations officer Ravinder Bhakar of the Western Railway.
He adds that though the detail may not be displayed predominantly in the newer stations, the Railways continue to use it internally. Explaining the other uses of the mean sea level, Bhakar said that the variation of the sea level between two connected stations is an important parameter.
“If one station is at 1000 metres above from sea level and the next is at 2000 metres, the locomotive will have to go uphill and will therefore need an elevated track as well as higher power. Also, other factors such as the turns and curves on the route for the tracks are determined by the height from the sea level,” Bhakar says.