A Pointer to the Past
From the Archives: NarrowBoat, Spring 2024
Andy Tidy
Andy Tidy uncovers unusual canal-related photos from the 1950s and finds out more
Sometimes you catch a fleeting glimpse of something out of the corner of your eye, but it’s only when you turn your head that you appreciate the significance of what you are seeing. Well, that was pretty much my experience when I first encountered the photographic records of the post-war Minor Revision Point Survey.
A bit of context
To be fair, the legwork for this research was undertaken by Duncan Moore who was trawling various council archives in the West Midlands, looking for photos of abandoned sections of the Birmingham Canal Navigations. It was during one of these visits that he came across a series of photos that can best be described as curious.
Among the many street scenes, there were a liberal number of canal-related images or, to be more accurate, partial canal shots. Rather annoyingly, centre stage in all these old photos were men holding 2ft-long white wooden arrows and information boards bearing reference data. At first glance the almost-comedic arrow-wielding gents in collars and ties, which dominate the scenes, caused me to dismiss the entire set of photos.
But then, on closer inspection, I began to realise that the backgrounds offered a fresh level of insight and detail of the local canal network and, in particular, the lost elements.
The subjects being highlighted are often an obscure corner of a bridge, a manhole cover, the end of a wall or even a bolt sticking out of a post, which was all rather frustrating given I was searching for lost canal structures or panoramas. But, being ever curious, I started to do a bit of digging into what these very formulaic photographs were all about, and I discovered that they are the legacy of the Minor Revision Point Survey undertaken in the mid-1950s.
Looking towards Gladstone Road on the Halford Branch in 1956, with Ridgacre Bridge out of sight.
The Halford Branch in 1956, between the footbridge and junction looking into the Ridgacre Oil Works.
Halford Branch and Ridgacre Bridge in 1956, from the western end of the footbridge through to the site of the Waterloo Ironworks.
Halford Branch from Gladstone Road in 1956, including the drain cover, a revision point which has survived.
The south-west corner of Ridgacre Bridge, looking west down Church Lane.
The north-west corner of Ridgacre Bridge in 1956, with Ridgacre Ironworks beyond.
South of Ridgacre Bridge, looking towards the Jesson Branch entrance, in 1956.
Looking towards Ridgacre Bridge in 1956, with the towpath bridge over the Cyclops Ironworks basin.
The north-west corner of Davies Colliery Bridge in 1956, looking along the Ridgacre Branch.
All images courtesy of Sandwell Archives.
History of the surveys
In the days before satellites, the creation of new or revisions to old maps relied on a lot of shoe leather, tape measures and trigonometry (a subject that loomed large in my pre-computer-era mathematical education).
The first major coordinated mapmaking survey of the nation took place during the canal-building era, starting in 1791, and was a project referred to as the Principal Triangulation. This initiative involved surveyors going out to establish a set of defined triangulation stations across the country, points which were made out of large stones with deep holes drilled in them. This survey took over 50 years to complete and, by the time mapping revisions were needed, almost 100 years had passed. Predictably, many of the location stones created for the original survey had been lost or removed.
Creating a network of fixed locations lay at the core of manual mapmaking and, in addition to ensuring the reference stones remained in situ, the other challenge was producing effective records so that later surveyors could find them again. Sadly, the Principal Triangulation project was rather deficient on both counts, with reference stones being used that could be moved, and poor record-keeping of their whereabouts. The location registers sometimes included vague instructions like “ask the farmer at Holly Bank Farm for the stone’s whereabouts”, which assumed the farmer would survive until the next surveyor arrived maybe 100 years later!
Fast forward to 1935 and a nationwide programme of retriangulation was initiated, starting with the construction of a series of ‘trig points’ on mountains and high ground, landmarks which have stood the test of time and continue to identify the high points of our upland locations. Their grooved tops offered firm location points for surveyors’ theodolites, from which the country was divided into a series of massive initial, or primary, triangles. These triangles were then broken down into smaller and smaller triangles, with each subdivision needing well-defined and immobile reference points.
To deliver the level of detail needed in urban areas, teams from Ordnance Survey were sent to the nation’s major cities to identify and record a set of fixed Revision Points within the existing built infrastructure, and use these to undertake their new mapmaking calculations. These Revision Points needed to be both enduring and identifiable by future surveyors, a lesson they had no doubt learned from the 18th-century Principal Triangulation debacle.
Having selected a suitable Minor Revision Point, carefully staged photographs were taken which included a ‘hymn board’ bearing the date, OS Grid Reference and image reference number. Because the mapmaking measurements were to be accurate to the centimetre, the exact point being used was identified by the white arrow. The need for accuracy accounts for why these arrow-wielding responsibilities were being taken so seriously. Advertisements were placed in local newspapers asking the populations to cooperate with the surveyors, and let them photograph their properties, if approached. However, not everyone got the message and, along with crowds of bemused onlookers, signs had to be erected to the public, such as, “Please don’t move my tripod”.
The Revision Point archives today
The end result of this remapping project was a huge mosaic of candid images showing fragments of the British postwar urban landscape as it really was. These massive catalogues of Revision Point photos were maintained by Ordnance Survey and continued to be referred to until the 1980s when satellite imagery took over, rendering a large part of my maths syllabus obsolete. After that time, these huge collections of photos were either donated to local archives or simply dumped.
I find it a little sad to observe the effort that went into the Minor Revision Point Survey, painstakingly recording urban reference points to serve as markers for future surveyors who would never follow. Not only was the science of trigonometric mapmaking about to be consigned to the scrapheap, the whole urban landscape was reconstructed, wiping away all those carefully recorded reference points.
To put some scale to this resource, the Manchester-based Timepix project has what is probably the most developed archive containing 23,000 images, logged, scanned and mapped. However, this barely scratches the surface as a further 300,000 images have been identified and are waiting in the wings for processing. Similar collections of Minor Revision Point photos existed in many other conurbations, and some found their way into the local archives of the West Midlands. Given the extent of the established canal networks in the region, these collections will undoubtedly include many inland waterway subjects.
Perhaps a good way of illustrating the potential of this resource is to focus on the short Halford Branch, a very obscure lost canal which existed in what is now Sandwell, including the towns of Oldbury and West Bromwich. To help you locate this minor waterway, you need to leave the BCN New Main Line at Pudding Green Junction halfway between Smethwick and Tipton. You then turn right at the top of Ryders Green Locks, continuing along the now-impassable Wednesbury Old Canal to the site of the old Swan Gasworks. At this point you would turn right again onto the Ridgacre Branch, still in water but inaccessible since the 1997 Black Country New Road was built across it at water level. Then, just before the end of the Ridgacre Branch, you would have come under Davies Colliery Bridge (now destroyed) and turned right into the Halford Branch, built in 1828 and abandoned in stages from 1919.
Halford Branch
Nothing much has survived of this branch, bar a couple of slight humps in Church Lane, suggesting the places where the Ridgacre and Church Lane bridges used to span the canal channel. For many years the only evidence we could find of this waterway were the entries in the BCN maps and a number of wartime aerial photos in the ‘Britain from Above’ series. In addition, we have a few water level photos taken by Hugh Potter in the early 1970s, when he managed to get a boat a short way beyond the turnover footbridge at the start of the branch.
I know that many readers refer to the National Library of Scotland’s Side by Side mapping service to follow this type of exploration, but in this instance I fear they are doomed to disappointment. For some reason the online 1885 map covering the Ridgacre network of canals has been omitted, but reference to the paper version reveals the Hall End Grease Works at the start of the branch, which we see had been significantly enlarged in the later photos. This was followed by the Cyclops, Waterloo, Ridgacre and Hall End Ironworks, all grouped near Ridgacre Bridge. Between the two Church Lane bridges there was the Oriental Tube Works, a site which expanded during the war and, given the redacted legends on the photographs, was presumably undertaking an activity that was significant to the war effort. The far end of the branch was used to service the Hall End and Shrubbery Brick Works, with a terminus basin beyond Church Lane Bridge using tramways to reach the collieries to the north, until these closed down and the basin sold in 1919.
The differences between the landscape seen on the 1885 15in-to-1 mile survey and the aerial photographs taken a few decades later are striking, and it’s clear why a new survey was needed in the mid-20th century.
Much to our delight, we discovered a substantial collection of Revision Point photos covering the canal line starting with the Davies Colliery Bridge at the entrance junction, followed by the canal channel leading to Ridgacre Bridge and some channel shots halfway along towards the site of Church Lane Bridge near the original terminus. There are also some wider area photos looking away from the bridge parapets and into the adjoining ironworks yards, offering a primitive form of street view.
I felt compelled to try and work out if any of the Minor Reference Points being highlighted in the Sandwell Archive had survived the 70 years of subsequent progress. While the pitched-roofed buildings of the Oriental Tube Works seen across the canal from Gladstone Road appear to remain in place, the old canal frontages have all been remodelled, wiping away the detailed reference points. However, with the aid of Google Street View, it is possible to recreate photo 15a and maybe, just maybe, the drain cover being highlighted is still in the same place as its contemporary counterpart in front of the works gate.
Taking these sources together, it has been possible to compile a remarkably comprehensive record of how this obscure little BCN backwater used to look.
Images courtesy of Hugh Potter
Conclusion
Perhaps the most exciting thing about the discovery of the Revision Point photos is that, in addition to the few prints held in the Sandwell Archive, there are many more negative images waiting to be reviewed.
But that is far from the end of the story, because it appears that much of the OS collection was given to local councils, who then archived them in offsite storage facilities. The challenge is that, like the Principal Triangulation location records before them, the whereabouts of these collections have been lost, and many local archives don’t know what is held where.
Who knows how many post-war canal photos exist buried in these forgotten archives? With over 100 images being taken for each square kilometre, the scope is huge and it’s very likely you will be seeing a lot more inland waterway photographs featuring earnest men holding funny white arrows.
