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As far as is known underground and surface railway systems generally operate as a single service
without sharing facilities with other utilities. Safety considerations may dictate such separation.
However there are precedents such as tramways sharing services with roads in some cities such as
Geneva. Thus there may be cost advantages when an underground railway is to be built directly
under a road (e.g., London's Circle Line) to have common utility tunnels constructed alongside the
railway but separated by a reinforced concrete wall.

3.1 Opportunities for Infrastructure Sharing in Central City Locations

Opportunities for infrastructure sharing occur when several services need to be provided along a
common path to buildings or other locations such as where sensors or actuators are to be located.

3.1.1 Urban Corridors with Direct Trenching
[b‐1] shows a specification of a corridor with a metro (surface tramway) in the centre of the corridor.
Lines and electric power are separate from the other utilities in the corridor. This is illustrated in
[b‐1, Figure 5:37].

Figure 3 – Typical Utility Corridor Arrangement for Streets with Metro/Tram Lanes
[Source: Abu Dhabi Utility Corridors Design Manual, b‐1]

The operation and maintenance of the utilities will benefit from efficient and effective coordination.

Inter‐agency coordination during the installation and/or operation and maintenance activities will
maximize the benefits and ensure the following [b‐1]:

 Reduction in road maintenance costs [b‐1]
 Provision of smoother roads with fewer closures for maintenance/rehabilitation activities [b‐1]

 Provision of cost effective engineered solutions which are suitable for the local conditions [b‐1]
 Promotion of consistent policies which eliminate disputes among stakeholders [b‐1]
 Expediting project delivery and avoidance of project delays in the preliminary engineering, pre‐
construction and construction phases [b‐1].

3.1.1.1 Advantages of Trenching (direct burial) include:
 Initial costs may be lower because of the avoidance of the cost of the utility duct and subsequent
installation of the cables into such duct
 Planning time needed among stakeholders is minimized

 Maintenance workers can focus their expertise (training) on one utility

ITU‐T's Technical Reports and Specifications 393