Volume Ten - Pre-Victorian to the Present Day - Even more aspects - Investigation into the Condition of the Ely River Subway 1991 . . .

Subway Alignment :

The location of the demolished end of the Subway identified on the surface using the electro-magnetic equipment did not correlate with the alignment shown on the archive drawings and confirmed by taped dimensions taken during the survey. It is probable that due to the depth of the demolished end of the Subway the equipment had identified a shallower service, possibly a metallic water main, into which an energy field had been induced from the Subway below.  Drawing 1542/05 shows the alignment of the Subway and the location of the demolished end drawn at a scale of 1:500. The alignment is based on the archive drawings, Ordnance Survey sheets dating from 1920 to 1955, dimensions taken during the survey. All this information corresponds satisfactorily at a scale of 1:500.

TABLE 1 : CONDITION OF TUNNEL BY RING NUMBER :

Ring Nos.	Description of Condition	Comments	Photos
001-050	Paint system intact especially to upper ring segments - some flaking and rust staining evident. Elsewhere, paint flaking reveals slightly surface corroded and pitted surface, especially to lower segments. Condensation noted to tunnel crown. Ring conditions generally deteriorating with increasing chainage.	No loss of section to structural components. No corrosion to bolts.	3/1 3/2 3/3 3/4
051-100	No significant change in condition of lining noted. Paint system generally intact to upper ring segments, although two areas of historic water ingress noted between adjacent ring flanges evidenced by rust staining. Lower segments in generally poorer condition than upper segments and first indication of salt bearing water ingress noted at Ring 96 as evidenced by white deposits at the ring joint.	No loss of section to structural components.	3/5 3/6