The two class-I officials are attached to the Divisional Railway Manager (DRM) office here.
Those who have been arrested include a senior divisional engineer (class-I), divisional engineer (class-I) and chief office superintendent (class-3), said a statement by ACB.
The officials had demanded Rs 1.25 lakh to issue work order to the complainant Rajendrasinh Zala who was awarded the contract by Rajkot division to supply water, said the statement.
According to ACB police inspector K H Gohil, the complainant's firm won the contract to supply water to various railway stations from Wankaner to Aliyabada.
Apart from audio devices used during the trap, Zala also submitted an audio recording to the ACB as an evidence to prove that the trio had asked for money over phone, said the release.