The incident occurred near Prasannayapalli when Girish Naidu (31) and Arvind Kumar (35) were engaged in some work on the Railway Iron Bridge.
Girish Naidu, who was working as site coordinator, was a close relative of Andhra Pradesh's Civil Supplies Minister Paritala Sunita who hails from the same district while Arvind Kumar, fibre executive engineer, was a native of Guntur district.
Though the accident is believed to have occurred around 8 p.m., it was known only in the early hours of Thursday as relatives began a search for them as there was no response on their mobile phones.
The two had gone to the railway bridge to check some number as they had to make an application to railway authorities for permission to lay fibre optic cable across the track for a 4G tower being installed in the area.
Police suspect that the duo came under Bengaluru-Bhubaneswar Prashanti Express as they could not move out of the bridge on time.