Unusual sight at 30th Street Station: British police on patrol.

Five British police officers, each capped with a traditional Bobby's helmet, patrolled 30th Street Station this morning as part of an unusual exchange program.

Along with heavily-armed Amtrak police, the unarmed British Transport Police officers - don't call them Bobbies - screened the baggage of train passengers bound for New York City and Washington D.C.

"We share a determination to protect the traveling public from the threat of terrorism and this gives us a chance to share best practices," said Superintendent Philip Trendall of the British Transport Police.

As two K-9 teams snaked through the rush-hour crowd searching for explosives, the British officers watched closely and occasionally offered advice to their American counterparts.

A half-dozen Amtrak police recently returned from the United Kingdom, where they participated in a similar exercise.

Ed Phillips, the deputy director of operations for Amtrak security, said the goal was to provide maximum protection "without creating an airport environment."

"We want to maintain the convenience of rail travel," Phillips said. "You come to a station you don't have to take off your shoes or walk through a metal detector."

It's a sentiment shared by Trendall.

"This partnership is very important to us," Trendall said. "It gives us the opportunity to learn what works well here in the U.S. and what we take back to the U.K. we can use to counter terrorism without inconveniencing the traveling public."