Singla allegedly took the bribe from a member of the Railway Board, Mahesh Kumar, who has also been arrested by the CBI in Mumbai. Kumar was recently promoted as Member (Staff) and was aiming the more lucrative position of Member (Electrical) and allegedly paid the amount to secure the post.
Two other persons, including Manjunath who acted as Kumar's conduit, have also been taken into custody.
The CBI made the arrests after acting on a tip-off and tracked Kumar's movements and phone calls and finally caught him at his residence when he was making the payment.
The arrest comes as a huge embarrassment for the Congress, particularly after it took over the charge of the coveted railway ministry after a long time. The party, which is leading the ruling coalition at the Centre, is already battling a series of corruption charges.