Economics of Building Above Operational Railways
Creating a new development above or adjacent to a busy transport interchange, such as a railway station, has many obvious advantages including city centre location, connectivity, shorter travel time for occupants and close proximity to other amenities.
However, the reason many such sites still exist in a relatively undeveloped state is the particular design and construction challenges they present.
Below are some of the issues that design teams and contractors will have to take into account when contemplating works on or near the operation railway, often referred to as over site development (OSD).
- Survey and information gathering – knowing the location, condition, age, use and operational criticality of existing assets will help with decision making and risk management
- Asset protection – in addition to operational railway equipment, the sites are often intersected by major utility services and inevitably existing assets will have to be monitored, protected, diverted, decommissioned or relocated (perhaps numerous times)
- Working method – severe restrictions on how, where and when work can take place often lead to extensive temporary works and constraints on working hours, spaces and compounds
- Logistics – the railway may present logistical opportunities for plant and materials to and from site and the use of specialist vehicles, however engineering trains and the paths they require are critical resources and the railway operator will prioritise their use accordingly
- Programme – scheduling practitioners should be wary of long lead times for access, multiple phases and handovers, extremely limited working hours and numerous external dependencies
- Attendance – works in the operational environment will require attendance from specialist teams under the asset owner’s control for example to provide electrical, signalling and control isolations and possession management
- Approvals – the design and delivery teams will need to obtain many forms of approval from the asset owner throughout the process to ensure design, specification, method, access and future maintenance arrangements are acceptable
- Compensation – the asset owner is contracted to provide trains paths for the train operators and any disruption to planned services will attract compensation and may require diversionary or replacement services
- Cost Premium – special features for cost planners to consider include significant non-productive and premium rate labour in possessions, low plant utilisation, abnormal preliminaries, asset protection teams, insurance contributions and restricted supply chains
- Whole life – careful consideration and early agreement of who will own and maintain, new and altered assets once they are commissioned into use will benefit all parties
When contemplating a development in an operation railway environment there are many ways to mitigate the time, cost and risk impacts including:
- Early engagement with sector experts from all disciplines
- Build open and honest relationships with the asset owners
- Invest in the survey and information gathering phase
- Minimise the work required to be carried out in an operational environment
- Plan the works early and stick to the plan
- Seek opportunities to share pre-planned possessions and blockades wherever possible
- Allow realistic cost and time provisions that recognise the constraints
Developments of this nature are far from straightforward, but when done well the results can be spectacular and rewarding for all concerned.
Read more about our work in the rail sector here.