Total U.S. coal rail traffic for the week ended Dec. 10 went down 5.4% year over year to 87,929 carloads, according to data from the Association of American Railroads.

Year-to-date coal rail traffic tumbled 21.4% through the week, a continued downtrend leading to the largest annual decline since record keeping began in 1949.

The total rail traffic for the week was 538,932 carloads and intermodal units, slipping 1.1% compared with the year-ago week.

BNSF Railway Co.'s coal shipment volumes clocked in at 38,576 carloads in the week ended Dec. 10, down from last week's 40,871 carloads, and lagged 7.2% behind the year-ago week's shipment.

Union Pacific Corp.'s coal shipment volumes this week were at 23,323 carloads, up from 23,149 carloads last week, but sank 11.8% compared to last year's weekly volume.

Eastern railroad CSX Transportation Inc.'s shipment volumes of coal stood at 17,589 carloads, down from the last week's 18,531 carloads but slightly increased by 0.7% compared to the same week in 2015.

Norfolk Southern Corp.'s coal shipment volumes totaled 17,054 carloads for the week, up from last week's 16,259 carloads but 8.3% lower than the same week a year ago.

Kansas City Southern Railway Co.'s latest weekly coal shipment volume showed 4,138 carloads, up from 3,696 carloads the previous week. The railroad serves 10 U.S. states and Mexico.

US coal output slides 2.1%

Unlike the previous weeks, total U.S. coal production for the week dropped 2.1% year over year to 15.8 million tons, compared to 16.2 million tons during the same period last year, according to data from the U.S. Energy Information Administration.

For the 52 weeks ended Dec. 10, production reached 730.4 million tons, declining 19.7% year over year, while year-to-date coal output slumped 18.9% year over year to about 695.4 million tons through Dec. 10.

The western region's coal production for the week totaled 8.8 million tons, representing a 7.5% year over year tightening from the prior year's 9.5 million tons. Data for the Western region covers Powder River Basin mines.

Coal production from Appalachian mines clocked in at 3.8 million tons, rising 2.2% from the year-ago week.

The Interior region climbed 9.8% to 3.2 million tons, compared to 2.9 million tons a year ago. Interior region data covers mines in the Illinois Basin.

The EIA's production data is derived from rail carload estimates.

Data collected by S&P Global Market Intelligence from railroads indicate both cars originated on their lines during the week and cars received from a connecting railroad during the same week.