SubscribeLong journeys from city centres to international airports are often tiresome. A cost-effective and environmentally friendly way to improve passenger logistics while reducing traffic congestion and air pollution is provided by the combination of flight check-in at railway stations and automated baggage handling on trains.
Due to the existing traffic conditions, rail is the best means of transporting people the 35 km. separating Hong Kong Island and Hong Kong International Airport (HKIA). When the latter opened in 1998, an express line linking the locations had already been constructed.
In the knowledge that the large quantities of luggage carried by airline passengers would slow embarkation times and cause crowding on platforms and trains, the managers of the Mass Transit Railway Corporation decided to supply two main stations with check-in facilities - thus allowing travellers to off-load their cases as early as possible in their journeys. To minimise the impact of this on train scheduling, the need for an automated baggage handling system was also perceived, which ALSTEC Ltd. was subsequently contracted to design, manufacture, install and commission.
Departures
Check-in desks manned by airport personnel are located at Hong Kong Central and Kowloon stations. The procedures followed are virtually identical to those at the airport. Bags are weighed, labelled and taken away by conveyor; passengers are issued a boarding pass and a rail ticket. They can then travel on any train to HKIA, within the limitations of their flight time. This allows tourists who must vacate their hotel by midday but are not due to depart until the evening to sightsee or shop unencumbered in the interim.
At both stations, the incoming bags are transferred by conventional conveyors to packing positions, where they are placed in special containers holding an average of 20 items (which at this stage are not yet sorted by flight). Operatives use hand-held scanners to record the unique bar codes on the containers and all luggage labels. Thus, each bag is identified with a specific container. During peak periods, the loading process continues until the containers are full. Off-peak, a 'time out' is enforced, to ensure they are dispatched within a few minutes, irrespective of the number of items they hold.
After being weighed, locked and sealed with a unique tie strip, the containers are moved to the train loading area by roller conveyors. Approaching trains automatically radio data to the platform controls - regularly updating information concerning which containers they hold.
Train Loading / Unloading
To each of the 11 trains is coupled a dedicated baggage car. This has five doors, all of which face the platform. Behind the central one is a reversible roller conveyor; behind the other four is a reversible right angle deck conveyor, connected to a pair of reversible roller conveyors. These 13 conveyors - arranged in a line - can accommodate up to 13 containers, which can be loaded in just 65 seconds. Physical stops prevent the latter from tipping while the train is in motion. (In addition, an emergency walkway runs parallel to them within the car.)
Each of the five loading units on the station platform consists of a reversible roller conveyor which can be raised, lowered, or moved horizontally, to compensate for the train stopping accuracy of ± 150 mm. and the varying suspension heights of the carriages (due to their loading, wheel wear, etc.). A small drawbridge conveyor is incorporated to bridge the gap through the doorway.
The units automatically align with the doors before delivering containers, then return to their original location to collect any remaining. Once the first containers are transferred from the deck to the roller conveyors, another batch is inserted. This procedure is then repeated if necessary. Empty containers are removed from the carriage using the loading sequence in reverse, for return to the packing positions.
Station Equipment
Hong Kong Central station, the furthest from the airport, has a single platform. A double closed loop of conveyors transfers containers between two packing positions and the train loading area. A spur deals with out-of-gauge bags, which are received from the check-in facility by lift, and are placed in dedicated containers not used for normal luggage.
Kowloon station has two platforms: one up-line, where containers are loaded, and one down-line, where empty containers are received. The latter are lifted over the tracks by an overhead gantry connected at each end with a double hoist incorporating a pair of reversible conveyors. Two parallel conveyors lead from the exit to four packing positions, and from these to the train loading area.
While it is possible to load or unload 13 containers through all five doors at one station, usually six are swopped over at Hong Kong Central, and seven at Kowloon.
The airport terminus has three levels, linked by two double hoists, each incorporating a pair of reversible conveyors. Incoming trains arrive at the highest, and the loaded containers extracted from them are taken to four unpacking positions at the lowest.
Here, for security reasons, they are reweighed, their seals are verified prior to being detached, and the luggage label on every bag removed is rescanned. Empty containers are then returned to the middle level for insertion into departing trains. Everything is done by conveyor, except for the actual unloading of items - which are also later subject to Hold Baggage Screening.
A standard loading area and a single reversible conveyor at Tsing Yi station allow containers to be withdrawn from one train and put into another if necessary. In addition, large horizontal ball tables enable the emergency manual transfer of containers from a carriage in either of two refuge sidings to one on the main track (or visa versa).
Controls
Under normal conditions, commands are issued to the baggage handling equipment via programmable logic controllers, by a governing system which obtains data from the various hand-held bar code scanners and the numerous sensors detecting the presence of containers.
Management information systems at Hong Kong, Kowloon and HKIA monitor equipment performance, generating maintenance and other reports from accumulated statistics. Workstations at these locations and Tsing Yi also perform a monitoring role, and enable local control panels where appropriate. Manual operation of the equipment is possible, but often only for the purpose of recovery from fault conditions.
For further information, contact ALSTEC Ltd., Cambridge Road, Whetstone, Leicester LE8 6LH. Tel: +44 (0) 116 201 5057. Fax: +44 (0) 116 284 3851. Web site: www.alstec.com Email: airport.sales@alstec.com
