A passenger train was creeping along painfully slowly when finally it creaked to a complete halt.

One passenger saw a conductor walking by outside and yelled, "What's going on?"

"Cow on the track!" replied the conductor.

Ten minutes later, the train resumed its slow pace, but within five minutes, it stopped again.

The same woman saw the same conductor walking by again and leaned out the window and yelled,

"What happened? Did we catch up with the cow again?