Talking of trains...
Paddy goes for a job as a signalman. He's taken up to the signal box and the display board and controls are explained as he nods with understanding.
"Right" says the examiner, "now I'm going to test you." He points at the board and says "What would you do if there was a train coming along there and one in the siding there?"
Paddy says "No problem. I'd pull dat lever dare and press dat button"
"Good" says the examiner. "Now what if you had two trains there and there and one in the station there?"
"No problem" says Paddy. "I'd pull dose two levers and push dat button and flick dat switch dare."
"Excellent" says the examiner. "Now your final test. What would you do if you had two trains coming along there and there, an express train coming along there and two stationary trains there and there?"
Paddy thinks for a minute and says "I know, I'd phone me bruder Mick."
"Why" asks the examiner, "is Mick a signalman?"
"No no" replies Paddy, "but I'm pretty sure he's never seen a train crash!"