Subway station rehabilitation / renovation
projects, also known as subway rehabilitation projects, are
among the projects with special needs. These projects have
special characteristics that differentiate them from other
types of construction projects. The most important
characteristics of subway rehabilitation projects from a
project planning perspective are the need to account for the
schedule of diversions, utility / infrastructure
relocations, piggybacking opportunities, special permits,
flagger availability, and work train availability.
Because of the special characteristics of subway
rehabilitation projects, some considerations for scheduling
these projects shall be applied with special attention and
emphasis. The following provides key considerations for
planning and scheduling of these projects. This list is not
meant to be comprehensive. Instead, it identifies some of
the key considerations that need to be given to the planning
and scheduling of subway rehabilitation projects.
- Identify the activities that cannot be implemented
during normal service hours (e.g., the activities that
need diversion of train services). Examples include
activities on the platform edge and activities on,
under, or near tracks. If a project involves working on
several stations on the same line, the stations that are
between two immediate switches can utilize the same
diversion (by piggy-backing on each other). Under these
circumstances, diversion-related tasks should be
scheduled properly to maximize efficiency.
Having multiple diversions on one line and between
different switches is called double-heating. If
the stations are not between two immediate switches,
diversions are not usually scheduled at the same time to
avoid double-heating and ensure train service
interruptions are minimized.
- Determine the preliminary number and type of the
required diversions, work-trains, and other special
services for the project. This determination will help
the construction team consider diversions, work-trains,
and other special services as project resources. This
approach helps the construction team to identify the
resources that are constrained. By using proper resource
management strategies such as resource planning and
optimization, the construction team can ensure it
obtains access to these special services when the
project needs these services.
- Review the special services identified with operations
departments to ensure availability. If the requested
diversions cannot be accommodated during required time
frames, the scope of work, design requirements,
alternative construction methods, job phasing, or the
project timeline should be reviewed and revised based on
the available diversion plans. In addition to time,
budget, and resource constraints, the availability of
diversions is one of the major constraints that impacts
subway rehabilitation projects.
- Identify the areas and equipment that cannot
concurrently be closed or taken out-of-service in each
subway station to ensure of continuous and safe
operation of the station. Examples include entrance
stairs, platform stairs, mezzanine areas, elevators, and
tracks. For instance, if two elevators in one station
exist and upgrading both elevators are in the project
scope of work, working on the two elevators at the same
time may not be permitted.
- Identify hazardous materials such as lead, asbestos,
and mercury. Performing abatement operations might be
necessary before the commencement of work in areas in
which a hazard may be present. In these cases, direct
communication and coordination between the client,
contractor, and environmental agencies is crucial to
identify the proper course of action. In addition,
removal of these materials during the construction phase
may require special permits and equipment for which
contractors should plan in advance.
- Identify the long-lead and client-furnished items.
With respect to long-lead items, an opportunity may
exist to fast-track some activities by creating an
overlap between the design and procurement activities
for the long-lead items. Moreover, early order placement
for long-lead items plays an important role in making
sure that long-lead items will be delivered to the
project in a timely manner. In addition, the
construction management needs to properly identify the
client-furnished items and account for the possibility
of receiving these items later than expected.
- Identify the activities that are supposed to be
executed in areas that are not under the authority of
the construction team. Examples include utility
relocations or working in a public street. In addition,
it should be determined if these activities require
additional permits (e.g., DOT permits). The project team
should be aware that these tasks have the potential to
delay the project to a great extent because the project
team usually has little control on expediting the permit
application, inspection, or review processes.
In summary, from a project planning perspective, some of the
key characteristics of subway rehabilitation projects that
differentiate these projects from many other construction
projects include the need to account for the schedule of
diversions, utility / infrastructure relocations,
piggybacking opportunities, special permits, flagger
availability, and work-train availability. As such, some
considerations for planning and scheduling of these projects
shall be applied with special attention and emphasis.
Dr. Mirhadi and Dr. Terouhid are principal consultants at
Adroit Consultants, LLC.