Underground Container Mover

The port of Antwerp is one of the most important economic portals in our country  thanks to her geo-economic location, the industrial activities in the port  and the excellent connections with the inland.

In  the last decades the centre of gravity in our transport system has shifted to the transport of containers  and recent  studies have shown that container  transport will continue to grow at an explosive rate over the coming years.

To meet the market requirements with regard to container movements within the port , additional intraport  transport facilities  will have to be foreseen in addition of  the existing transport infrastructure such as motorways , roads, railways and inland navigation waterways.

The underground container transport system UCM (Underground Container Mover) is a new  fully automated intraport transport system which offers the ability to transfer containers most efficiently within the port  area. With UCM we can transfer containers from the docks on the left bank of the river Scheldt to the railway freight complex and the internal navigation hubs on the right bank and vice versa with quasi unlimited capacity and “just in time”. The transport system UCM has a large number of advantages regarding to the existent transport modi in the harbour:

-          Independent of the existing transport infrastructure

-          No influence of weather conditions

-          24 h on 24 h

-          Almost unlimited transport capacities

-          Inexpensive and reliable

-          Durable technological development

Technological description of UCM (case study)

Introduction

This case study on  the UCM transport system handles about an underground connection realized by means of pipelines between  the existing railway freight complex  , the inland navigation hubs at the quays B1 and B2 and the container terminals  at the quays on the Delwaide dock on the right bank of the river Scheldt , both quays of the new  Deurganck dock on the left bank and the container terminals  Europe and Northsee at the Berendrechtsluis and a transferium to be organized  in Wijnegem  with direct connections to the existing motorways E313 and the Albertcanal.

 

The pipelines are placed in loops  by which the transport takes place in a closed circuit  and the capacity of the outward transport is equal to the capacity of the return transport.

An electro-mechanically driven haulage cable  is located within the tunnel and  pulls the container trailers , which are placed on rails , at a constant speed between 5 and 20 km per hour.

The pipelines are connected with the underground loading/discharging stations which are divided over the loops. These loading- and discharging stations are in connection with loading / discharging quays at the surface with vertical shafts.

Utilities are also located in the pipelines for electric power supply, steering and safety measurements.

Traction

The individual passive trailers or transport platforms operate in the pipelines  on rails . The rails are mounted  on the pipe wall through a steel structure. Through this the weight of the vehicle and its load will be carried over on the tunnel wall .

Each individual passive trailer is equipped with a double grip for coupling the trailers to a main haulage cable extending along the loop .This main haulage cable is divided into  sections  with a working length of 2 to 5 km depending on the slopes and the installation possibilities  of the power stations and each section is driven by  electric motors equipped with frequency speed variation regulator , installed in power stations. Each power station  contains the drive mechanisms for 2 sections , so the inter distance of the power stations is 4 to 10km. The power of the electric  motors will be  between 125kW and 250kW. At the other end of each  section  a chamber with a tensioning device for the cables is installed.

 

The haulage cable has a constant speed  on all sections and is guided in the tunnel by guide sheaves. This constant speed can be changed in function of the desired capacity of the UCM concept by the frequency speed variation regulators.

 The gauge of the grip is maintained small to permit its passing this guide sheaves. There is a double grip for security and to pass from one section to the other. The operation of the grips is automated.

Each section of the loops is equipped with a second haulage cable with own drive mechanisms and electric motors . Both drive systems are fully independent for maximal operational  reliability.

The diameter of the haulage cables is about 50mm.

Trailers

The trailers  or transport platforms are of the type low-bed trailer, through which the container can be accurately centered in the tunnel section and through which the tunnel diameter can be kept as small as possible. The largest containers will fit then precisely in a tunnel with an internal diameter of about 4,2 meter . Furthermore, the trailers have two independent railway wheel-axles at the front and at the back, by which the vehicles can perfectly make horizontal turns with  minimum friction-resistance.

Each individual passive trailer is equipped with a double grip for coupling the trailers to  the main haulage cable. There is a double grip for security and to pass from one section to the other. The operation of the grips is automated.

The wheels operate on ball-bearings such as railway carriages for restricted maintenance and a long lifespan.

Wear and tear is minimal, maintenance very restricted and there is no corrosion thanks to the relatively low speed of the conveying system and the ideal atmosphere with controlled humidity and temperature in the pipeline. The trailers are multifunctional, they can support containers of 20 feet or  40 feet and are foreseen of an  automatic clamping systems to hold the containers.

The system and trailers are calculated on the maximum carrying-capacity  of 40 feet containers including the maximum charge of the container and a safety factor for taking into account the dynamical effects during the loading and unloading.

Maintenance and storage 

At one or more locations an underground storage and maintenance facility will be foreseen. For that purpose a switch in the railway tracks in the tunnel at the entrance of the storage and maintenance facility is installed. When the switch is set to divert a trailer out of the system the jaws of the grips of this trailer are opening automatically  and the trailer goes to the sidetracks in the storage and maintenance space. On these side tracks containers can be moved by secondary haulage cable loops at a low velocity. Place to storage 50 to 100 trailers will be foreseen . Through  openings in the ceiling trailers can be removed to the surface or lowered from the surface to the system .A switch at the exit of the maintenance and storage place will put the trailers on the main tracks of the system while the grip of the trailer automatically takes the main haulage cable in the loop.  This maintenance and storage place can be combined with the control and  operation room of the UCM system.

Loading- and unloading platforms

In the underground station at the height of a loading / unloading platform, a second track is build over a length of 30 meter next to the main rails. Upon this a portal vehicle, equipped with a container lift is operating over this parallel railway. At the height of the vertical shaft, the container will be lowered from the quay towards the lift of the standing portal vehicle.  Further the portal vehicle will move forward over the parallel track until the speed of the underlying chain-link trailer has been reached. Then, the container will be placed on to the trailer with the lift and the portal vehicle will stop. Finally, the portal vehicle will return to its starting point to take up a new container.

Transport control

 The trailers on the track move around the loop with a constant speed and are encoded. Thanks to the electronic observance of this movement  containers  can be collected and delivered “just in time”. This traceability allows us to deliver the shipment in a controlled manner from the container quay to the predetermined destination, on the defined date and in the preferred order.

If we foresee several loading/unloading stations and spread these over the length of the quays,  we can make optimal use of the quays and the gantry cranes . This optimization can contribute to accelerating the loading and unloading of the ships and can optimize the work  for the gantry  cranes, forklifts and straddle carriers and limit their work  to  a minimum. Furthermore, the number of places on the stacks and the time of the container treatment in the port can be reduced by “just in time” delivery.

Construction of the tunnels or pipelines  with prefabricated pipe elements

Prefabricated pipe elements are limited in diameter. By the optimal position of the container in the pipe section ,  the diameter of the pipes can be limited  so  the pipelines can be constructed with the pipe jacking technique. This building method has a large number of advantages.

A pipe element is monolitic and  rigid . That makes that  the rails can be placed very precisely and durable in the tunnel. Moreover, there is little or no leakage because they have a limited number of seals and by the application of  a steel plate  liner in the concrete pipes, which we recommend, the pipes are connected to each other by welding  the steel liners and  the tunnel is 100% waterproof even under high water pressures. This impermeability is very important for the reliability and durability of the mechanical and electromechanical equipment in the tunnel specially in the deep lying sections under the river Scheldt and the docks.

Installation of the tunnels with prefabricated pipes

A number of vertical shafts will be build over the track with an inter distance of about 2 km . From these shafts the pipes will be pushed into the ground from  one shaft to the other by means of a tunnel boring machine and hydraulic jacks. Because the pipe joints can move without leaking  curved tracks can be executed horizontally as well as vertically. After the pipe jacking is finished, the  the steel plate liners will be welded  to each other, by which the tunnels will be 100% waterproof. After completion of the pipe jacking, cement mortar will be injected through injection points  in the pipe wall to stabilize the construction in the ground. The pipeline with prefab concrete elements in combination with steel plate liner is very durable and 50 years of guaranty and even more can easily be given on the whole construction. The vertical shafts can be used as emergency exit and entrance shaft for inspection and maintenance during the exploitation of UCM.

The current evolution of the tunnel boring technique with remote controlled boring machines and with electronically driven laser measurement technique permits to realize alignments with a very high accuracy ( a couple of centimeter ).

The admitted slope in the profile of the tunnel track is much larger than for example for railways (4/1000) and motorways( 8/100) by using the  haulage cable drive of the UCM system. In so doing, an ideal profile can be realized without additional costs for consolidation of the bedding of the waterways and with extra short slope entrances.

The reliability of the installation is the most important risk factor in determining the economic efficiency

The tunnels can be build in sections of 2 km and more. The completion deadline can be drastically shortened by undertaking several drives at the same time with several tunnel boring machines.

To secure the operational  security a fire detection system with CCTV  cameras is installed . A powerful ventilation system removes any smoke and excess heat . An automatic  foam extinguishing system similar to the systems used in the chemical industry is installed over the total length.

Alternative implantation

A possible and interesting solution for the UCM alignment on the container terminals is to let the container mover rise to the surface at the beginning of the loading- and unloading quay and move again in the underground at the end of the loading- and unloading quay.  In this above ground part of the loop  the containers are being loaded in the UCM system or are being discharged from the UCM system. The implantation of this aboveground part is situated on the place of the lane for the straddle carriers which are lying the closest to the quay and the ship so that the operations of the straddle carriers on the other lanes aren’t disturbed or interrupted in any possible way and the exploitation of the container terminal can continue uninterrupted. The containers will be lifted out of the ship by the loading/discharging cranes and will either be placed in the UCM system or on the existent lanes under the crane boom where they will be picked up by the straddle carriers and transported to the stack just like during the current terminal exploitation. When the containers will be loaded on the ship, they will either be picked up directly out of the UCM system through the crane and placed in the ship or from the lanes where they are put by the straddle carriers. The loading and discharging of the containers in or out the UCM system happens with the portal vehicles such as  with the original solution.  The big advantage of this alternative solution is the known fact that the containers have less actions to undergo because they are not stocked on a stack at first,  although this option remains still possible, and that the usual exploitation of the terminal can continue uninterruptedly for the other containers, while all the advantages of the UCM system will remain.