Rail Infrastructure

The rail infrastructure provides some unique challenges for specialist rope access contractors to work at height, especially to carry out structural inspections, investigations, maintenance and assessments.

The areas where these services are required include bridges, culverts, viaducts, retaining walls, coastal defences, wells, stations, roofs, embankments, tunnel shafts, tunnel portals, footbridges, aqueducts, mines, adits, rock faces and maintenance depots.

Network Rail and its main contractors are highly selective employers due to the complex and unique infrastructure involved. Network Rail has a very prescriptive specification for examining structures. The specification outlines the requirement of the examinations, the recording and reporting of the examination findings and provision of information for Regulatory Reporting. The purpose of and examination of a structure is to:

• Establish and record the condition of the structure
• Identify defects and record any significant change in the condition, loading or environment that may indicate or cause deterioration
• Provide sufficient information for the safe management of the structure and any management action necessary to maintain the safety and serviceability of the structure

The specification requires a tactile, or hands on inspection of all parts of a particular structure.

Before working on the railway infrastructure, consideration must be given to the rail specific safety competence training required, which includes PTS (Personal Track Safety), IWA (Individual Working Alone), COSS (Charge of Site Safety), PC (Protection Controller), ES (Engineering Supervisor, and PICOP (Person In Charge of Possession).

In order to employ and sponsor individuals with track competencies, it is also necessary to prove to Network Rail and its independent assessing companies that competence and operational procedures are in place (via Link-up). Those personnel certified competent to work on the rail infrastructure further required to comply with ever changing group and line standards. In particular for structures examinations, the current standards applicable are:

• NR/SP/CIV/017 Examination of Bridges and Culverts
• NR/SP/CIV/083 Examination of Retaining Walls
• NR/SP/CIV/085 Examination of Tunnels
• NR/SP/CIV/088 Examination of Buildings and Station Structures
• NR/SP/CIV/090 Examination of Coastal, Estuarine and River Defences
• NR/SP/CIV/092 Examination of Ancillary Structures
• NR/GN/CIV/041 Structures Condition Marking Handbook

Rope access companies have developed considerable consultancy and engineering work utilising rope access techniques on the rail infrastructure, as they have proved that this method of working:

• Affords a practical, safe solution with the ability to solve awkward and troublesome problems that would otherwise absorb a disproportionate amount of time or money
• Enables the rapid installation and dismantling of the access systems which therefore causes minimal disruption to occupants, pedestrians, traffic flow, and delays to trains
• Negates the requirement of specialist and expensive items of plant, scaffolding or equipment
• Enables affordable tactile examinations of all structural components that would otherwise require major investment to achieve
• Provides cost effective, fail safe methods of accessing awkward, high or otherwise inaccessible structures

Some of the more interesting structure/s inspected on Great Western Region includes:

Box Tunnel
One of the most interesting and challenging series of structures inspected utilising rope access techniques were the numerous structures above, below and within the prestigious Box Tunnel which is situated on Gods Wonderful Railway on the London to Bristol main railway line. Box Tunnel was constructed between 1836 and 1841, and was of course designed by Isambard Kingdom Brunel.

Successful completion of these inspections demanded considerable cooperation and liaison between the main contractor, Network Rail, the Ministry of Defence, and private land owners (shafts seem to be sunk in the most peculiar of places). Using combined specialist rope access and diving techniques enabled the successful inspection of six ventilation shafts (up to 100m deep), two ornate tunnel portals and a structure below the tunnel. The shafts provided unique challenges, particularly with regard to rescue provision in accordance with IRATA guidelines and providing ropes long enough to descend the shafts (ropes are not normally required to be that long!).

Royal Albert Bridge
Another unique structure examined in recent years is the historic Royal Albert Bridge. The site works for the examination of the Royal Albert Bridge concluded a complex planning process which included having a detailed method statement and risk assessment accepted by the main contractor. A pre-site visit was undertaken to enable the examination processes to be clearly defined. Consideration was given to the effect of the site works on the operational railway, waterborne traffic navigating a busy river, access to the structure, potential hazards, equipment required, personal protective equipment required, access equipment, safety boat cover, rope anchorage, environmental impacts, emergency procedures, welfare provisions and facilities, and a full methodology for undertaking the examination. Even with detailed planning, the final inspection phases were still dependent on favourable weather conditions, due to the high levels of exposure to rope access personnel working on the inspection. A safety boat was provided to Maritime and Coastguard Agency standards with VHF communications to the Queens Harbourmaster/Port control to back up the examination. After all this planning and effort expended to examine the structure, the authors of this document found the structure to be in a remarkably good condition!

Cornish Piers
Brunel constructed a total of 43 viaducts between Plymouth and Penzance. Harsh financial constraints combined with the geography of Cornwall tested Brunel’s skill in the design of cheap but effective structures, to carry his broad gauge railway across the many tidal creeks and deep river valleys which intersected the route. Brunel’s solution was to construct a number of fan type timber viaducts. However, shortly after construction, problems arose from a combination of factors such as inadequate timber protection, and the usual problems associated with constructing in timber – rot, fire etc.

Replacement viaducts were constructed adjacent to the timber viaducts (in order to maintain an operational railway). Following the construction of more substantial structures using more robust materials, the timber viaducts were then abandoned, but the masonry piers were left in place.
A number of the remaining piers were identified for examination, namely: Bittaford, Moorswater, St.Austell, Gover, Truro and Carvedras.

The examination of these structures provided some unique challenges for rope access personnel. The structures examined consisted of masonry piers in a variety of conditions, some of them were 45m in the air. Without the use of aircraft, a combination of techniques was required in order to gain access to the top of the structures. This included bolting and climbing the piers, simple abseiling, and the use of a bow an arrow to fire ropes over the top of the piers (and yes this was risk assessed!). Ropes were then anchored with ground anchors to enable the examinations staff to climb the piers.

Author - Dave Rylatt