Rail traffic on the Ratlam-Godhra section of the Delhi-Mumbai line was affected for about 20 hours after a stretch of track bed caved in at a bridge, an\u00a0official said today. The movement of trains on the section was disrupted for nearly 20 hours and the traffic was restored at 3.30 pm today, said J K Jayant, Public Relations Officer, Western\u00a0Railway (Ratlam Division). One of the tracks (up-line) was closed at around 7 pm on Sunday after it was noticed that a stretch of track bed (ballast) had caved in on a bridge between Banjranggarh and\u00a0Thandla Road stations on the Ratlam-Godhra section, he said. The track bed (ballast or crushed stones) is the groundwork onto which a railway track is laid. It is used to bear the load from the railroad ties, to facilitate drainage\u00a0of water, and also to keep down vegetation that might interfere with the track structure. The Indore-Pune Express was scheduled to pass on the damaged line when the information about the cave-in was received and the train was immediately stopped. Later, the entire traffic was diverted to the another track (down line), which delayed movement of trains, Jayant said. A couple of trains was cancelled or terminated ahead of their destination, he said. The affected stretch was repaired and tested at around 11 last night. However, the result was not satisfactory after an engine was made to pass through the track. Repair work was\u00a0again undertaken and the traffic was restored at 3.30 pm, he added.