The owner of the reindeer had contacted the railway company several times and been assured that the trains would travel more slowly past the animals, NRK reported.
However, it seems that the train drivers failed to receive the instruction, in a case that has shocked the nation.
Reindeer more or less roam free in Norway, with owners guiding the deer towards certain areas in winter to help them find food.
Due to difficulties in keeping the herd together, the keepers often alert train companies of their movements to avoid collisions.
Despite the precautions, NRK reported that more than 2,000 reindeer were run over between 2013 and 2016.
A railway spokesman told the broadcaster that reindeer keepers will be compensated for their losses.
He blamed the recent deaths on a technical fault in forwarding the message to drivers. An attempt to advise them of the herd's location at the last minute apparently came too late.
This video grab taken on November 25, 2017 shows a train driving past dead reindeer laying next to the railway near Mosjoen in northern Norway. AFP
More than 100 reindeer have been struck and killed by freight trains in Norway in recent days, in what has been described by radio broadcaster NRK as a "kilometre-long blood bath."
