ACR B727 STRIKES GND VEHICLE DURING WINTER CONDITIONS ON RAMP AT PHL.

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DURING A LIGHT/MODERATE SNOWSTORM IN PHL; OUR B727 WAS TAXIING TO OUR GATE. THE RAMP WAS COVERED WITH APPROX 2 INCHES OF SNOW. BRAKING AND MANEUVERABILITY WERE FAIR TO GOOD. WHILE ACFT WAS ON PARKING CTRLINE; THE L WINGTIP STRUCK A DEICING TRUCK PARKED NEARBY. MARSHALLERS AND WING WALKERS WERE PRESENT; BUT NOT ABLE TO TELL IF A CONFLICT WAS PRESENT UNTIL TOO LATE. THE SNOW COVERED THE SAFETY LINES SO NO ONE COULD TELL IF THE TRUCKS WERE IN THEIR PROPER POS. DAMAGE TO THE ACFT WAS SMALL; TRUCK WAS UNDAMAGED. I BELIEVE THAT THE INCLEMENT WX MAY HAVE AFFECTED THE GND PERSONNEL'S PERFORMANCE. I'M SURE THEY WANTED TO GET OUT OF THE COLD AND SNOW ASAP. IN ADDITION; THE MARSHALLER DIDN'T KEEP AN EYE ON THE WING WALKERS-- SHE WAS WATCHING THE ACFT ALIGNMENT WITH THE TAXI CTRLINE. SUPPLEMENTAL INFO FROM ACN 461253: SOMEONE OTHER THAN THE MARSHALLER SIGNALED THE CAPT TO STOP; BUT THE MARSHALLER DID NOT GIVE THE STOP SIGNAL. IT APPEARED THAT THE SAFETY CONES WERE IMPROPERLY PLACED AND THE MARSHALLER SIMPLY WASN'T PAYING ATTN. SUPPLEMENTAL INFO FROM ACN 461669: THE MARSHALLER; WHEN ASKED WHY THEY DID NOT SEE THE WING WALKER'S STOP SIGN; SAID THEY WERE NOT WATCHING THE WING WALKERS. BETTER TRAINING MAY PREVENT THIS; PLUS KEEPING SAFETY LINES CLR OF SNOW WOULD HELP.