The amount of time that cargo containers linger at the ports of Los Angeles and Long Beach appears to be decreasing, according to new data released Oct. 14 by the Pacific Merchant Shipping Association. The length of time that a container stayed on the docks before leaving by truck was 4.2 days in average in September, trimming the average by nearly a day from 5.1 days the previous month. Meanwhile, the average dwell time for cargo at terminals before departing by rail - while still a high average - was also down in September from the previous month, from 16.5…