Kalyanâs WCAM 3 # 21934 moves slowly to couple with the rake of the 1026 Up Pragati Express to Mumbai. The spikes above the insulators as well as the hanging strips (move by the wind) above the spikes are meant to scare away birds. The birdâs dropping on the insulators increases the chances of a flashover on the OHE due to the excellent conductive properties of the stuff !. Pune Jn., 2005-04-16. Apurva (iti@vsnl.com).