Maryville to Mollinsburn
The M73, despite being a relatively short route, is one of Scotland's most important motorways. Interchanging with the M74, M8 and M80, it is a key distributor road to the east of Glasgow. Devised at the same time as the M74 Hamilton Bypass, it was built as a high quality replacement for the A73 trunk road.
Originally built to rural motorway standards, the southern section has, since the 1990s, become increasingly urban in nature. The M73 has a mix of dual two, three and four lane carriageways with hard shoulders throughout. It was constructed as a single £9.5 million contract (almost £130 million in today's prices), and was opened to traffic in two stages on 19th May 1971 and 20th April 1972. A connection to the M8 Monkland Motorway followed on 23rd April 1980.
Plans for what became the M73 were first outlined in the Clyde Valley Regional Plan of 1949, although little progress was made at that time. In 1960, Glasgow based consultant Babtie, Shaw & Morton was commissioned by the County of Lanark to carry out detailed traffic studies and develop plans for new roads throughout the region. This work was keenly supported by the Scottish Development Department.
The route was developed in conjunction with plans for the motorway bypass of Hamilton and Uddingston, and was initially known as the Maryville to Pleaknowe Link Road. Designed to utilise the benefits of the new M74, and the (then recently upgraded) A8 and A80 dual carriageways, its primary purpose was to remove strategic traffic from the A73 trunk road. This route, which passed through the urban heart of central Lanarkshire, was congested by heavy vehicles travelling between England and Central Scotland. In effect, the selected corridor provided a western bypass of Lanarkshire and an eastern bypass of Glasgow.
A connection to the proposed Glasgow urban motorway system was considered essential, and Babtie worked closely with Scott Wilson Kirkpatrick to ensure the city's highway plans would tie into their neighbouring proposals.
M73 Construction Summary
Construction of the flyovers at Maryville Interchange was completed as part of the second stage of the M74 Hamilton Bypass scheme, completed in August 1968. Construction on the first section of M73 (between Maryville and Baillieston) began in March 1969, with construction taking two years to complete. The second stage between Baillieston and the A80 opened in 1972. The main contractor was Balfour Beatty.
Junctions on the M73 are numbered from south to north, from Junction 1 (Maryville) to Junction 3 (Mollinsburn). A fourth junction exists at the interchange with the M80, numbered Junction 4 on each route. Between Junctions 1 and 2 (Baillieston Interchange), the route is constructed to urban motorway standards with four traffic lanes and a hard shoulder in each direction.
This section of the motorway was widened between 2014 and 2017 as part of the M8, M73, M74 Improvements scheme. The project also saw the upgrade of the motorway communications system installed in 1994. Since the 1990s, the route has become increasingly urban in nature, as surrounding agricultural land has made way for new housing.
Mid-way between Maryville and Baillieston, a large viaduct crosses the North Calder Water. Despite its relatively short length, it's one of Scotland's most impressive steel box girder structures. This section of the motorway was lit with high mast lighting in the early 1980s.
As it approaches Baillieston Interchange, the M73 reduces in width. The nearside lane provides a free flow link to the M8 Monkland Motorway, whilst lane two provides a dedicated link to Baillieston Roundabout and the A8/A8(M).
The extensive Baillieston complex, encompassing over twenty bridges and spread over 110 acres, was completed in two stages. The first stage, completed in 1971, was a simple diamond interchange with links to the A8 for Glasgow and Edinburgh. The second stage, completed as part of the Baillieston to City Boundary section of the M8 Monkland Motorway followed in April 1980. Free flow, west facing slip roads were constructed for traffic heading to and from Glasgow. The "high loop" link from the eastbound M8 to the southbound M73 is perhaps the most iconic piece of what is Scotland's only four-level interchange.
North of Baillieston Interchange, the M73 reduces in width to dual two lane carriageways with hard shoulders. From here the motorway is built to rural standards and passes through agricultural and former industrial land. Around half a mile north of Junction 2, it passes over the line of the former Monkland Canal.
To accommodate the motorway, changes were made to the existing local road system. At Bargeddie, alterations were made to Manse Road and Cuilhill Road. The A89 at Coatbridge Road was also realigned. More extensive upgrades were required at Gartcosh where a short bypass was built around the west of the village. A new link between the A752 and Gartcosh Steelworks was also constructed. The works were closed in early 1986.
In the mid-1990s, plans for a new enterprise zone on the site of the former steelworks were developed. This led to the proposal for a new motorway junction which was opened in 1999 at Junction 2A (Gartcosh). Built by contractor R.J. McLeod at a cost of £3 million, the dumbbell type junction was designed by Babtie and made use of the overbridge on Woodneuk Avenue. Lanark County Council had pushed for a junction at Gartcosh during the initial design of the M73 but it was deemed unnecessary at that time.
The construction of the M73 severed the (then still operational) Monkland–Kirkintilloch Railway (the first railway in Britain to have the right to operate locomotives in its Act of Parliament) at Bedlay.
At the time of construction, the railway had already been cut back to between Bedlay signal box and Avenuehead Level Crossing, serving the National Coal Board sidings for Bedlay Colliery. Coal from Beldlay was transported by rail to Ravenscraig Steel Works until 1981. As part of the motorway construction works, a new chord railway line was constructed, including a trainman operated level crossing over Drumcavel Road to join with the NCB line at Leckethill Farm Level Crossing.
The last train over the original alignment ran on Saturday 18th October 1969 (a special organised by the Railway Society of Scotland). The new chord opened to traffic on the following Monday.
Construction of the M73 severed the Kirkintilloch-Monkland railway line. To mark its closure in October 1969, the Railway Society of Scotland organised a special service. Pictured is the service at Bedlay signal box. © James Watson
Until 2008, the M73 terminated on the A80 via two east facing slip roads. By then, peak time congestion resulting from the merge of the two routes was severe. As part of the upgrade of the A80 to motorway standards the interchange was completely remodelled.
Junction 3 (Mollinsburn) was upgraded to provide a connection to the (now bypassed) A80 towards Moodiesburn. West facing slip roads to the new M80 and a link to Westfield Road were also constructed, allowing for movements between all routes. M73 traffic merges with the M80 slightly to the north of the original junction, with dual four lane carriageways now provided.
Until November 1999, it was assumed that the M80 would be constructed in the Kelvin Valley, around a mile north of the existing A80. This option, ruled out on environmental grounds, would have required a northern extension of the M73. This is illustrated in many reports produced between the 1960s and 80s.
From the Archive
This article was first published in November 2020 and updated in October 2021.