INTANGIBLES

Goodwill and other intangible assets with indefinite lives are not amortized. Other intangibles with definite lives are amortized on a straight-line basis over their estimated economic lives. Goodwill and indefinite lived intangible assets are reviewed annually during the fourth quarter for impairment (See Note 2 “Summary of Significant Accounting Policies” included herein). Goodwill and indefinite live intangible assets were not impaired at December 31, 2018 and 2017.

The change in the carrying amount of goodwill by segment for the year ended December 31, 2018 is as follows:



	Freight			Transit
In thousands	Segment			Segment			Total
Balance at December 31, 2017	$	718,958		$	1,741,145		$	2,460,103
Additions	6,478			16,790			23,268
Foreign currency impact	(12,045		)	(74,782		)	(86,827		)
Balance at December 31, 2018	$	713,391		$	1,683,153		$	2,396,544

As of December 31, 2018 and 2017, the Company’s trade names had a net carrying amount of $582.8 million and $603.4 million, respectively, and the Company believes these intangibles have indefinite lives. Intangible assets of the Company, other than goodwill and trade names, consist of the following:



	December 31,
In thousands	2018		2017
Patents, non-compete and other intangibles, net of accumulated
amortization of $42,446 and $43,021	$	15,328	$	17,554
Customer relationships, net of accumulated amortization
of $158,533 and $126,824	531,761		583,459
Total	$	547,089	$	601,013

The remaining weighted average useful lives of patents, customer relationships and intellectual property were 10 years, 16 years and 13 years respectively. Amortization expense for intangible assets was $39.8 million, $36.5 million, and $22.7 million for the years ended December 31, 2018, 2017, and 2016, respectively.

Estimated amortization expense for the five succeeding years is as follows (in thousands):



2019	$	38,289
2020	36,552
2021	35,595
2022	35,283
2023	34,945