cowcatcher

Short definition from Wiktionary

Noun

1. 1
   A plough-shaped device affixed to the front of a locomotive (or other large vehicle), usually wedge or V-shaped so as to push or deflect objects on the tracks out of the way, to clear out the train's path and prevent the risk of derailment or major damage to it.
2. 2
   An advertisement at the start of a programme.