A Question Of Capacity Reprinted from the Light Rail Transit Association

A QUESTION OF CAPACITY

THE CAPACITIES of different modes of transport are generally quoted as 0-10 000 passengers per hour for bus, 2000-20 000 for light rail, and 15 000 upwards for heavy rail.

 

 

* Maximum capacity is only likely to be required for a few hours during peak hours, and even here there are likely to be variations both day by day and within each hour. The capacity required originates from the route’s social characteristics.

* As for the vehicles, buses have a comfort capacity equal to the number of seats, and a maximum capacity equal to seats plus standing load.

* In the case of trams, it is more complicated. The nominal maximum capacity is calculated at four passengers per square metre of available floor space (a reasonably comfortable level), plus the number of seats.

* As trams are designed to carry a large standing load, the ratio of standees to seats is quite high. The standing area is also important for the carrying of wheelchairs, pushchairs, shopping and sometimes bicycles. Some manufacturers quote maximum capacity using 6p/m2 while a figure of 8p/m 2 is used as a measure of crush capacity. This last figure is also employed to determine the motor rating of the vehicle.

* A further complication is that even when there are seats available, some passengers prefer to stand. This may be because they are only traveling for a few stops, that they want to stretch their legs, or may just prefer to stand.

* A tram’s comfort capacity can therefore be considered as the number of seats, plus the voluntary standees who may amount to up to 10-15% of the nominal maximum number of standing passengers.

ELASTICITY

* It is the difference between the average passenger load for any particular time and the crush load which gives light rail its Elasticity Factor, allowing it to cope with variations in conditions such as sudden surges or emergency conditions.

* Standing is made more acceptable by the design of track and vehicle, reducing the forces acting on the passenger to a minimum. This makes for a smooth ride, as well as ensuring ease of access, good support and the ability to see out without having to stoop.

* Where a route is mainly urban with short journey times, the number of vehicles required should be calculated on the nominal maximum. On longer journeys outside the central area, a lower level may be more appropriate, dependent on the route’s characteristics. Even on rural sections, there are likely to be a a number of short distance riders, and the loading factor will increase nearer to the urban area.

COMPRESSIBILITY

* While it might be thought desirable to offer every passenger a seat, it is in fact the ability to carry high loadings in a confined area (the Compressibility Factor) which enables light rail to achieve many environmental benefits, allowing large numbers of people to be carried without harming, and often improving, the features of a city.

* It is city centres where several routes combine that the most capacity is required. A typical situation could be a pedestrian street with six routes operating at 10-minute headway giving 36 double coupled trams per hour each with a capacity of 225. This gives a nominal capacity of16 200 passengers per hour which can be increased to 25 200 pph in extremis without extra vehicles.

Light rail is unique in this ability to operate on the surface with its capacity without detracting from the amenities which it serves. A further factor in setting the resources required is the need to lure motorists out of cars. The more difficult the traffic conditions, the higher the loading’s will be acceptable. It is however important that crush loads are not allowed for more than the shortest of periods on an infrequent basis, both to maintain customer satisfaction and prevent elasticity of the system being compromised.

* It is vital that public transport can cope with sudden changes in demand, such as extreme inclement weather or air quality violations which can cause private traffic to be halted. This is where the elasticity inherent in light rail is so beneficial in enabling an instant response in an economical fashion. A tram may be crowded, but its infinitelybetter than having to wait in the snow of smog untilextra vehicles are brought into service.

* It is this unique combination of Capacity, Compressibility and Elasticity rather than capacity alone which makes light rail so successful as an urban transport mode.

* Note Statistics are based on Karlsruhe, using GT/8 cars

 

Comments

2 Responses to “A Question Of Capacity Reprinted from the Light Rail Transit Association”
  1. eric chris says:

    All week, CTV in Vancouver is doing navel gazing news on the misery of commuting in Metro Vancouver. While the CTV might be entertaining viewers commiserating with the featured commuters in the stories, the CTV isn’t about to delve too deep into the cause and press any buttons to ruffle any feathers or make any sort of political statement to point any fingers. It’s to make people feel that they aren’t alone, in the commuting disaster created by the planners at TransLink, sigh, entertainment, not enlightenment.
    .

    “Commuter-Elle”
    Take Ellie (Elle) who’s the first commuter featured; she commutes between Coquitlam and Surrey for work. It can take over two hours to cover 20 km with “rapid transit” by TransLink. She’s stuck on “rapid transit” averaging 10 kph or less, door to door, twice as slow as riding the tram. In the video, Elle with CTV reporter in tow board the “frequent” bus required for rapid transit by rail. Bus service is so frequent that it has few people on board. It costs TransLink a small fortune to operate so frequently. No matter, it is to recycle Elle to “rapid transit” by rail. Here, Elle has to fight the crowds and the nightmare begins for Elle. From the rail “rapid transit” Elle has to make the mad dash to board “rapid transit” by bus. After many transfers, she’s relieved to make it home and end the ordeal on “rapid transit” taking about 90 minutes on this day, a good day, maybe TransLink was “tipped” off about the CTV filming in advance, compared to 20 minutes by car. Watch Elle taking “rapid transit” by TransLink:

    https://bc.ctvnews.ca/something-needs-to-change-fraser-valley-road-warrior-running-low-on-patience-1.3743052

    Elle has no car. She’s captive on public transit. She creates “ridership” for TransLink with each forced- transfer on “rapid transit”. TransLink makes Elle go through hell to create “ridership”. Every time that Elle transfers, TransLink ticks off the transfer as added “ridership” to count her one more time. Commuters like Elle are how TransLink creates “ridership” for more funding.

    With Elle riding trams and trolleybuses, TransLink loses transfers and “ridership”. This is bad for TransLink bolstering ridership to create the illusion that “rapid transit” increases transit use. Too bad for Elle whose commute, door to door, would take one-half as much time and be twice as fast with trams and trolleybuses having stops four times closer than the stops for “rapid transit”. It’s all about “ridership” and keeping public transit crowded and slow for more funding. No trams and trolleybuses for Elle, public transit stays crowded and slow for Elle :(

    http://commonground.ca/the-unaffordable-subway/

    “Commuter-Anne”
    High rise towers along the three rail “rapid transit” corridors are wiping out detached housing in Vancouver to make housing unaffordable in Vancouver and make commuters move out to Coquitlam and Surrey where new detached housing is being built beyond the “rapid transit” by rail. Most commuters drive from Coquitlam and Surrey for work and the few unfortunate ones take “rapid transit”. In the second video, watch the featured “road warrior”, Anne drive from Clayton Heights (Surrey) to Vancouver. Feel her pain. Missing from the story is the reason for her pain: “rapid transit” and the concomitant high rise towers making Vancouver unaffordable and causing her to live in Surrey to create all the road congestion on Highway-1.

    https://bc.ctvnews.ca/something-needs-to-change-fraser-valley-road-warrior-running-low-on-patience-1.3743052
    .

    “Commuter-X”
    Coming up on the not too controversial commuting features by CTV is commuter “X” from North Shore; it will be a doozy. Here’s one thought: replace the “SeaBus” between North Shore and Vancouver with one six lane, 3 km twin span, bridge for trams and cars before the Lions Gate Bridge becomes the next, falling apart Pattullo Bridge disaster, by TransLink. It will be money well spent.

    http://www.drba.net/delawarememorialbridge.aspx

  2. Haveacow says:

    A great article. Keep it up.

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