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| | London Underground @ HotAndCold.com (Hot and Cold) (Site not responding. Last check: ) |
 | | Stock on sub-surface lines is identified by a letter (such as A Stock, used on the Metropolitan Line), while tube stock is identified by the year in which it was designed (for example, 1996 Stock, used on the Jubilee Line). |
 | | Lines of both types usually emerge onto the surface outside the central area, except the Victoria Line, which is in tunnel except for its depot, and the very short Waterloo and City Line, which has no non-central part and no surface section. |
 | | The lack of lines south of the Thames is sometimes attributed to the geology of that area, the region being almost one large aquifer. |
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