It happened around 1:00pm at the Whitford Rail Station in Exton.
An Amtrak repair technician had been dispatched to the area to isolate a switching problem and saw a man standing on an aluminum ladder, leaning against a signal line while cutting it with a handsaw.
The technician called police and when the officers arrived, the man tried to run away, but tripped on the rails and fell down.
Officers took him into custody without incident. The man was identified as James F. Martin, 40, of Birdsboro, Pa.
Martin had already cut a 75 foot length of the copper wire away from the lines and was in the process of taking more, presumably to sell for their scrap value.
The cost to repair the damage done by Martin is estimated at $10,000.
Officials say dismantling the signals lines in that manner jeopardized rail traffic and put the lives of passengers and rail employees in peril.
Martin was booked and arraigned on 3rd degree charges including Risking a Catastrophe, Theft, Receiving Stolen Property, Criminal Mischief, and Criminal Trespassing.
He was arraigned at the Phoenixville District Court and committed to the Chester County Prison in lieu of $75,000 cash bail.
