ADIT & PASSAGES

Passageways/Adit's are vital areas, that not only connects station to the entrances, but gives transit systems the power to extend the station to distant areas and enhance transportation linkages. They are important for multitude of other reasons, some of which are denoted below. Whilst the terms passageway may be common in most systems, HK uses the term adits.

Passageways are also challanging to design and expensive to construct.

The physical and metaphorical linkage graphic above seeks to underline importance of passages and adits in station planning.

Firstly, from a statutory, life safety point, referencing NFPA130, the requirement of 'Point of safety' as defined in section 5.3.3.2, provides a framework where station planners are able to connect station box to the ground level via passages, irrespective of the length that the passengers need to walk (+ 6 minutes). This statutory scenario assumes the passengers can escape from the remotest place in the platform to a point of safety in less than 6 minutes, where another statutory compliant section takes over. Passageway/adit compartment are designed to enable passengers to egress the station for an indefinately more, ' fire engineered' time, to reach the entrances and the plce of ultimate safety. This is possile as passageway is separated from the station box by systems that allows its own life safety tenability's, such as detectors, smoke extraction, suppression systems, etc. Please refer later sections for sizing, life safety.

Next, more mature systems will use the passageways to link the transit system to higher catchment areas, by increasing the traditional catchment circle, or a plan that is either obround, or more biomorphic, shape that is centered around the entrances. See three diagrams to the below left. These are an important reminder not to have a cookie cutter station typologies for the entrances and the short passageway connecters. Adapt them for a best possible station ridership diagram.
If you take the below third diagram. Long passages ways and remote entrance permits unfavorable disposition for the station box (Required due to engineering reasons). It could be that the relatively remote entrances is near a built form which has substantial footfall - such as shopping centre, stadium, huge residential building, etc. All of which then makes the Station work much harder.

PASSAGEWAY LEVEL OF SERVICE

Level of Service (LoS) is a good design metric to review what a transit system design delivers to the passengers, in term of spatial limitations, distance of the station box from the entrances, etc. For example passengers walking 6 minutes of to reach a transit system is considered acceptable. This is usually drawn as a radius of a circle with the center line on the middle of the station box..

Lets see what that means?

Let's assume we walk at a speed 1.2 m/s
in 6 min, we will walk 6 x 60 s x 1.2 speed = 432 meters.

Which means that any distance outside of this is not taken as a catchment area

Taking the logic as stated above, if we note that we all consider the station to be the entrances, not the center of the station box. Then passengers will be happy to walk around 400m to any station entrances, then walk more to the actual station platform. Enabing us to have a larger catchment footprint.

This is part of the design standard in the Hong Kong MTR (Not seen in other systems). Where the secondary LoS is then to ensure that passengers are able to walk from the remote entrances to the platfrom in 6 minutes of less.

Here is another scenario. if you needed a longer passageway length yet providing a similar LoS to the users. What would you do? (Meaning if you need a longer passageway or adit than ~400m?).
Well! you use travellators. Here is how.

We assume that people will use the travelators.
That they will walk on the travelators.
The speed of a travelator is 0.5 - 0.7m/s
We walk at an average speed of 1.2m/s
The resultant walking speed of person on the travelator is 1.2 + 0.5 (Or 0.7)m/s = 1.7m/s to 1.9m/s
In 6min, we can walk 6 x 60 x 1.7(1.9) = 612m (Or 684m). Almost 150% longer.

Trottoir roulant rapide (TRR)

guinnessworldrecords.com/world-records/83543-fastest-moving-walkway

A high-speed moving walkway (or travelator) at Montparnasse metro station in Paris, France, moves commuters at 9 km/h (5.6 mph), the speed of a slow run and around three times as fast as regular moving sidewalks. The 180-m (590-ft) long Trottoir Roulant Rapide ("fast rolling pavement") was built by the French company CNIM and installed in 2003. Due to the high speed of the central section, acceleration and deceleration sections at either end of the walkway help adjust users' speed before entering or leaving the walkway. The walkway originally sped along at 12.1 km/h (7.5 mph), but this was reduced after repeated falls in the acceleration and deceleration zones.

PASSAGEWAY ISSUES

Longs passageways in underground spaces can cause human discomforts, such as claustrophobia, loss of sense of direction, etc. Further there may be a need to address many issues such as:

Location for elder citizens, or disabled ones to have rest, seating
Address acoustic issues due to echo, reverberations
Differing smoke management (Spaces divided into smoke zones to allow smoke management, in case of fire in the passageways/adits), etc

PASSAGEWAY VISUAL IMPACTS

These Photographs Capture the Colorful Architecture of Europe’s Metro Stations | ArchDaily

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