The change in the carrying amount of goodwill by segment is as follows:


In millions	Freight Segment		Transit Segment		Total
Balance at December 31, 2025	$	8,567	$	1,649	$	10,216
Additions/adjustments	8		475		483
Foreign currency impact	(1)		(77)		(78)
Balance at September 30, 2026	$	8,574	$	2,047	$	10,621

As of September 30, 2026 and December 31, 2025, the Company’s trade names had a net carrying amount of $897 million and $851 million, respectively. The Company believes these intangibles have indefinite lives.


	September 30, 2026						December 31, 2025
In millions	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Backlog	$	1,368	$	(691)	$	677	$	1,311	$	(613)	$	698
Customer relationships	2,262		(630)		1,632		2,000		(550)		1,450
Acquired technology	1,662		(836)		826		1,570		(731)		839
Total	$	5,292	$	(2,157)	$	3,135	$	4,881	$	(1,894)	$	2,987

At September 30, 2026, the weighted average remaining useful lives of backlog, customer relationships and acquired technology were 7 years, 16 years and 6 years, respectively. The backlog intangible asset primarily consists of in-place long-term agreements acquired by the Company in conjunction with past acquisitions. Amortization expense for intangible assets was $89 million and $267 million for the three and nine months ended September 30, 2026, respectively, and $77 million and $219 million for the three and nine months ended September 30, 2025, respectively.

Amortization expense for the five succeeding years is estimated to be as follows:


In millions
Remainder of 2026	$	89
2027	$	355
2028	$	353
2029	$	351
2030	$	338