The social effects of urban mass transit consist of tangible and intangible effects. The latter is quite difficult to be quantitatively estimated when we use the method of market valuation.

城市轨道交通社会效益包括有形效益和无形效益，其无形效益的估算难以用市场评价法来定量化。

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This has been a tremendous track record, partly based on sheer good luck, but also on more intangible effects.

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