Mumbai is the cleanest state capital, according to the Swachh Bharat ranking announced by the Union Urban Development ministry; and even Maharashtra Chief Minister Devendra Fadnavis declared Mumbai to be open defecation free.

Yet the Suburban Railways has identified stretches that have 'night soil and unhygienic track conditions' and cautioned motormen to go slow there. 'Night soil' is a sweet-smelling term for human excreta. Speed restrictions have been imposed for other reasons such as construction of bridges, newly laid lines, presence of level crossing, defective rail, etc.

Central Railway's (CR) situation is shittier than Western Railway's (WR). CR authorities have issued speed restrictions on more than 60 locations, while the WR's count is at 15. CR has asked the motormen to slow down to 20-30 kmph to avoid human casualty.

"It is surprising that motormen have been asked to slow the trains down only because people are defecating next to the tracks," said a miffed senior CR official. "Why can't the administration send the Railway Police Force to remove these encroachers from rail land?"

Some of the prominent stretches where trains will have to slow down, but not smell the roses, are near Parsik tunnel, between Kanjurmarg and Vikhroli, King's Circle-Mahim, Mahim-King's Circle, and the chord line on the Kalyan end of Parsik tunnel. It is not clear whether tracks on the stretch between Govandi-Mankhurd on Harbour Line have also deteriorated due to man curd.

Railway union members say it is very difficult to maintain and clean the tracks. "The problem escalates before monsoon as we are expected to remove garbage and human waste," said a member of the Central Railway Mazdoor Sangh.