Edinburgh, Leith, and Newhaven Railway first share call 1836
The Edinburgh, Leith & Newhaven Railway opened from Canonmills to Newhaven on 31 August 1842. The line was extended to Granton, with a station on the central breakwater of Granton harbour on 1846, and on the same day their Newhaven station was replaced by a new one named Trinity. They added a branch to North Leith on 10 May 1846, with one intermediate station at Bonnington. Thereafter the company renamed themselves the Edinburgh, Leith & Granton Railway (the notice above the portal in Waverley station being inaccurate).
The company had always planned to tunnel through to a new terminus in the city centre, but this was bitterly opposed by residents of Edinburgh's affluent New Town district, who envisaged their homes subsiding into the tunnel. Eventually a route was agreed on which kept the tunnel under the middle of streets and residents thus placated, the tunnelling got underway. The extension to the new terminus, Canal Street, was opened on 17 May 1847, and Canonmills station was renamed Scotland Street, to avoid confusion.
Canal Street stood at right-angles to the Edinburgh & Glasgow station, Edinburgh General. The latter had opened on 1 August 1846 and stood back-to-back with the North British Railway's North Bridge terminus. As a result, both these stations became considered as one, commonly referred to as "Waverley", and the name stuck. There was a tight curve between Canal Street and Edinburgh General to facilitate goods traffic.
Shortly after opening Canal Street, the ELGR was taken over by the Edinburgh & Northern Railway, who built the line through Fife from Burntisland to Tayport. The latter opened their route from Ladybank to Perth in 1849, and changed their name to the Edinburgh, Perth & Dundee Railway. Around the same time they changed the name of Canal Street station to Princes Street.
By 1860 Waverley station was so crowded for the traffic it had to accommodate that it was the talk of the railway companies of the UK, as this was having a knock-on effect causing delays across the British railway system. The NBR were often lambasted and lampooned by the press, they had to reopen the former Edinburgh & Dalkeith station at St Leonards to some services for the summer of 1860, and it was obvious that something had to be done. In 1862 the NBR purchased the EDPR outright and began work on a new line to Leith and Granton via Abbeyhill. This new line ran under Easter Road, Leith Walk and Ferry Road, before meeting the EPDR line at Trinity. It also crossed the North Leith Branch on the level at right-angles at Bonnington, and a triangular junction created to connect the branch to the NBR Granton line.
The new line opened on 22 May 1868, with stations at Easter Road and Leith Walk. On the same day, Princes Street and Canal Street stations closed and the NBR, who had also absorbed the Edinburgh & Glasgow Railway in 1865, commenced demolishing it and the first rebuilding of Waverley station.
Scotland Street tunnel was disconnected and closed off from Waverley but not abandoned. Instead the NBR found a novel use for it; growing mushrooms. As the tunnel was double-track, boxes of mushrooms were kept along one line, with wagons of fertilizer to cultivate them pushed up from Scotland Street. So lucrative was this business to the NBR that the operators became a subsidiary NBR body; the Edinburgh Mushroom Company.
The Caledonian Railway had been operating to Edinburgh since 1848 and opened their new terminus, Princes Street (not to be confused with the EPDR station of the same name) in 1870. In 1900 they submitted plans to parliament to build an underground line the length of Princes Street to a new terminus adjacent to Waverley station, and continue from there down to Leith. The NBR opposed this move bitterly in parliament, arguing that the new CR station would interfere with 'vital workings' of the NBR. These 'vital workings' were in fact Scotland Street Tunnel and the Edinburgh Mushroom Company. It shows how much clout that the NBR held in parliament that they incredibly won their case and the CR Bill was defeated. There was however one provisio; that the NBR build their own line to Leith. This was to be the genesis of the Leith Central branch.
The mushrooms were wiped out by a parasite in the early 20th century. After the grouping, the LNER lifted the tracks in the tunnel. During World War II, the LNER had offices built in the tunnel as their emergency divisional HQ (railway author G.F.Fiennes also recalled it being used as a shelter for passengers). In the 1950s the offices in the deepest part of the tunnel - below the top of South St Andrew Street were used for radiation bombardment experiments. In the 1960s a car dealer used the tunnel to store cars in, but thereafter it lay abandoned. A raid on Royal Mail carriages in Waverley in 1980, in which the thieves used the tunnels to steal mail bags, led to the tunnel being gated off in Waverley and King George V park (site of the former Scotland Street yards). In the late 1980s the southern portal became a ventilation shaft for Princes Mall shopping centre.
Many uses have been mooted for the tunnel since. The abortive Edinburgh Crossrail of the late 1980s envisaged a north to south rail link which would have included use of the tunnel in part. A more recent idea was to use it as a passenger link to the new Edinburgh bus station, possibly with retail units along it.
All such plans have come to naught and Scotland Street Tunnel, still unknown to many Edinburgh residents and visitors, remains abandoned below the city streets.