Footage showed a large section of rail track, embankment and trees swept downhill.
Flash floods and a landslide in Central Kenya killed at least 45 people and injured over 110 others on Monday as floodwaters swept away houses and cars in the town of Maai Mahiu, the government said.
Police initially blamed the flooding on a burst dam; however the Ministry of Water later said it was caused by a river tunnel under a railway embankment becoming blocked with debris.
"The water (eventually) swept the railway line and started moving downstream with a very high speed and velocity causing destruction of property and loss of lives," the ministry said.
Two local residents confirmed the Water Ministry's account.
"While 45 bodies have already been retrieved along the path of the flash floods and the landslide, search, rescue and recovery is ongoing," Interior Cabinet Secretary Kithure Kindiki said in a statement.
Footage showed a large section of rail track, embankment and trees swept downhill.
Hours after the rain had let up and floodwaters began to recede, local residents pulled motorcycles and household belongings from the mud.
Joel Kuria, a farmer, was awoken by screams and the trembling of the house he shares with his wife and two children.
"It was very dark, but we managed to leave the house in time before the gushing waters swept away everything including our livestock," he told Reuters from where he was camped out in the town centre.
"The grumbling sound was scary and was worsened by screams of victims being washed downstream."