The Tyne Bridge is reported as being either 389A or 397.72B metres long.

Reference A does not cite the source of this figure, whereas reference B reports the source of it's data as one of the Proceedings of the Institution of Civil Engineers and as such the figure of 397.72 metres is likely to be the most reliable.

Please see the related links.

Sources:

A Tyne Bridge Wikipedia Entry - reliability questionable in this instance.

B Tyne Bridge - Structurae Website.