Tunnels/ventilation shafts

[Ploughman]

I must have been imagining it then when working on the track over many years in Standedge tunnel that there were no shafts.
Shafts were used to extract the material and play a part in maintaining the alignment by use of Theodolites, telescopes and indicators all using the shaft.
Most of the spoil extracted went up the shafts and was dumped around each shaft on the surface.
Some of the I think 8 shafts (could be more need to check that) have been infilled but at least 5 are visible on Google Maps Satellite view.
The links to the old tunnels and the Canal tunnel act as a pressure relief but that is by accident and not by design.
Ventilation in this tunnel and most others rely on the prevailing wind either directly blowing through or by the action of the wind blowing across the top of a shaft and creating an updraft.

 

[Philip]

Seven of the ventilation shafts are over the canal tunnel and one over a side adit. Some of the shafts were constructed with the building of the railway tunnel but located over the canal with the side adits there to let ventilation go from the canal to the railway tunnel. It mentions this in the forgotten relics article.

 

[Cliveblackpool]

I must have been imagining it then when working on the track over many years in Standedge tunnel that there were no shafts.
Shafts were used to extract the material and play a part in maintaining the alignment by use of Theodolites, telescopes and indicators all using the shaft.
Most of the spoil extracted went up the shafts and was dumped around each shaft on the surface.
Some of the I think 8 shafts (could be more need to check that) have been infilled but at least 5 are visible on Google Maps Satellite view.
The links to the old tunnels and the Canal tunnel act as a pressure relief but that is by accident and not by design.
Ventilation in this tunnel and most others rely on the prevailing wind either directly blowing through or by the action of the wind blowing across the top of a shaft and creating an updraft.

That sounds like hard work, using a whim etc to extract the material and water from the tunnel vertically. The problem building an additional tunnel.
In hard rock I would have thought they would start with a pilot tunnel, working from both ends, and at the same time sunk the ventilation shafts. Water, and spoil (in mine trucks on rails) would come out by gravity, that is the tunnel slopes towards the entrances, with the summit near the centre. The spoil hopefully would be used/ lost in an embankment further down the track.
I believe that when pilot tunnels met they were a maximum of a foot out!
Those few windless days a year would not been good with coal fired engines!