Properties

9 Months Ended

Sep. 30, 2021

11. Properties

The following tables list the major categories of property and equipment as well as the weighted-average estimated useful life for each category (in years):



Millions, Except Estimated Useful Life			Accumulated		Net Book		Estimated
As of September 30, 2021	Cost		Depreciation		Value		Useful Life
Land	$	5,283	$	N/A	$	5,283	N/A
Road:
Rail and other track material		17,882		6,790		11,092	43
Ties		11,292		3,469		7,823	34
Ballast		6,032		1,828		4,204	34
Other roadway [a]		21,294		4,538		16,756	49
Total road		56,500		16,625		39,875	N/A
Equipment:
Locomotives		9,362		3,760		5,602	17
Freight cars		2,143		815		1,328	25
Work equipment and other		1,126		392		734	18
Total equipment		12,631		4,967		7,664	N/A
Technology and other		1,205		534		671	13
Construction in progress		869		-		869	N/A
Total	$	76,488	$	22,126	$	54,362	N/A



Millions, Except Estimated Useful Life			Accumulated		Net Book		Estimated
As of December 31, 2020	Cost		Depreciation		Value		Useful Life
Land	$	5,246	$	N/A	$	5,246	N/A
Road:
Rail and other track material		17,620		6,631		10,989	42
Ties		11,051		3,331		7,720	34
Ballast		5,926		1,753		4,173	34
Other roadway [a]		21,030		4,329		16,701	48
Total road		55,627		16,044		39,583	N/A
Equipment:
Locomotives		9,375		3,555		5,820	17
Freight cars		2,118		789		1,329	25
Work equipment and other		1,107		351		756	18
Total equipment		12,600		4,695		7,905	N/A
Technology and other		1,199		520		679	13
Construction in progress		748		-		748	N/A
Total	$	75,420	$	21,259	$	54,161	N/A

[a]Other roadway includes grading, bridges and tunnels, signals, buildings, and other road assets.