The River Bollin in Macclesfield flows under the railway line in a couple of culverts, the largest a brick and stone arch around 270m long.
There's a few small tunnels that used to connect in, likely from disused mills, sadly these are mostly blocked off. Eotech paused near the mouth for one after seeing a pair of eyes in the torch light, as we got nearer a large long brown mink/ferret slinked away from the waters edge and disappeared.
A pair of box tunnels with counterbalanced flaps outfall just upstream of the main culvert, a grill inside each was covered in jam rags and prevented access to the CSO within.
An concrete outfall for a small watercourse soon turned to stone within. It gave us a good stoop down 180m of stone arch, brick egg, concrete box, RCP and a good play around with handheld shots. Eventually it emerged back into the open at a wooden sluice.
Back at the Bollin there's another shorter culvert that's propped up on dubious supports and what looked like a pigeon death pit.