Underground Freight Transportation. A new development for automated freight transportation systems in the Netherlands.

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1 Underground Freight Transportation. A new development for automated freight transportation systems in the Netherlands. By Ben-Jaap Pielage Abstract Underground freight transportation (UFT) is introduced as a possible alternative for transporting freight. The latest developments on UFT in the Netherlands are discussed and the -ASH project is used to illustrate the designing of such highly automated freight transportation systems. The prototyping and testing performed for this system are briefly presented and some general conclusions resulting from the UFT studies in the Netherlands are discussed. The goal of this paper is to present UFT as a new development for automated freight transportation systems and discuss some of the transport technological aspect as they may be of interest for future developments in intelligent transportation systems. Index terms Automated underground freight transportation systems design & prototyping. I. INTRODUCTION Underground freight transportation (UFT) is presented as one of the possible solutions for the transport related problems in the Netherlands. Although the growing mobility of people and goods contribute to our prosperity and well being, it also generates congestion and environmental damage. With the increasing transport demand, problems arise in the transportation and distribution of freight, especially in densely populated areas. Expansion and improvement of existing infrastructure for the various transport modalities are not always possible in these areas. Moreover, most of the existing modalities would not contribute to a better living environment. This creates opportunities for automated underground freight transportation systems. Aalsmeer Schiphol Hoofddorp. The designing prototyping and testing of this automated freight transportation system will be discussed briefly. The goal of this paper is to present UFT as an interesting new development for automated freight transportation systems and discuss some of the transport technological aspect as they may be of interest for future developments in intelligent transportation systems. II. UFT DEVELOPMENTS IN THE NETHERLANDS During the past years several feasibility studies on underground freight transportation have been performed, starting in 1995 with the -ASH project, which will be discussed later. In 1997 an Interdepartmental Underground Transport Task Force (IUTTF or IPOT in Dutch) was formed consisting of representatives from several Dutch ministries. With IPOT the Dutch government aimed to structure and co-ordinate research on underground transportation[1][2]. The two main fields of interest were: 1. Transport of gases and liquids (traditional pipeline transportation) 2. Underground transport of freight or Underground Freight Transport (UFT). This paper focuses on UFT systems. Figure 1 shows two artist s impressions of possible UFT systems for the future [3]. The picture on the left presents a UFT system for urban areas servicing retailers, hotels and catering, offices and other urban consumers. The picture on the right shows a UFT system connecting industrial areas, logistic centers and/or multi-modal hubs like airports. This paper presents the development of UFT in the Netherlands during the last 5 years and then focuses on the -ASH project as this project is expected to become the pilot project for UFT in the Netherlands. -ASH is the Dutch acronym for Underground Logistic System - B.A. Pielage M.Sc. Delft University of Technology Faculty Design, Engineering & Production Section Transport and Logistic Systems Mekelweg 2, 2628 CD Delft, The Netherlands B.A.Pielage@WbMt.TUDelft.nl Figure 1. Artist s impressions of UFT system; in urban areas (left) and at Schiphol airport (right). The different UFT projects in the Netherlands are presented in Figure 2 [1][2]. Feasibility studies for underground freight transportation in urban areas have been completed for Utrecht, Twente, KAN (Knooppunt Arnhem Nijmegen),

2 Tilburg, and Leiden. -ASH, Rotterdam and Geleen / DSM focus on underground freight transport for connecting industrial and/or logistic centers. In order to test the transport technological aspects developed within the projects, a TestSite was developed in Delft. b Utrecht Considering these conclusions some remarks can be made. First, underground transportation is not new. The Mail Rail system in London for example has been operational since 1927 [5]. This automated underground transportation system is operated by Royal Mail to move mail across London and is still in use today. An impression of the terminal is presented in figure 3. Studies in the Netherlands today focus on UFT as a part of the total transport network rather than a separate stand alone system. More on UFT can be found in the ISUFT conference proceedings, see [1] and others. Twente Schiphol Leiden TestSite KAN Rotterdam - port area Tilburg Geleen / DSM Figure 2. Overview of UFT (or ) projects in the Netherlands The final IPOT report [4] presents some general conclusion on UFT systems, the most important being: 1. UFT could technologically handle a considerable part of the domestic freight transport, reaching 70% for urban areas. Combination of flows and connection to a multi-modal transport network is however necessary. 2. Investment costs for underground transportation systems are high. However, if the government would finance the infrastructure, as it does for roads, rails and waterways, a profitable exploitation is possible. 3. UFT systems do not always have to be fully underground. Undisturbed infrastructure above ground is worth considering. Using separate infrastructure above ground maintains the benefits of undisturbed transportation but requires far less investments. 4. There is not jet sufficient support for large-scale national implementation of. For urban areas a follow-up study is recommended to deepen the knowledge. For -ASH sufficient is known and it is recommended to use the -ASH as a pilot project. Figure 3. Underground MailRail in London. A second remark; UFT systems, seen as automated freight transportation systems using undisturbed infrastructure, can benefit from experiences gained from other transport automation projects such as the automated container terminals of ECT at the port of Rotterdam [6]. Figure 4 shows an Automated Guided Vehicle (AGV) used at the ECT container terminal in Rotterdam. Figure 4. AGV used at ECT. The -ASH project will be used to discuss and illustrate underground freight transportation as this project is considered to become the pilot project for UFT in the Netherlands and it has initiated interesting research and developments on automated freight transportation systems.

3 III. INTRODUCING THE -ASH PROJECT The goal of the -ASH project is to transport flowers and other time-critical cargo through an automated underground transportation system between the flower auction in Aalsmeer, Schiphol airport and a railway station near Hoofddorp. This would create an undisturbed link between the flower auction at Aalsmeer and Schiphol airport and the rest of Europe by means of an international network of high-speed freight trains. The project was initiated because the deteriorating accessibility of this area increasingly threatens the position of the Schiphol airport and the flower auction Aalsmeer. The is regarded as a possible solution for the problem in the Schiphol area creating good connections between these two economic centers and their hinterland. An overview of the total system is presented in figure 5. The three areas Hoofddorp, Schiphol and Aalsmeer will be connected to each other by single bored tubes. Automated vehicles will carry the time-critical cargo through the tunnels. The system connects to the rail terminal at Hoofddorp, where the cargo is handled automatically and synchronized with the new high-speed rail cargo concept. At Schiphol airport several freight terminals connect with the underground system. The terminal at Aalsmeer connects the flower auction to the underground transportation system. the testing performed at the TestSite will be presented in this paper. IV. DESIGNING THE -ASH TRANSPORTATION SYSTEM Different steps can be distinguished when designing transportation systems [3]. First we define the system boundaries and functional requirements. Then the types of cargo and the prognosis for the desired period of operational use are determined. Different concepts can then be generated for the method of transport and the material handling, and different terminal layouts and system variants can be created. When designing such highly automated systems, attention must be paid to the design of the control and information system. These aspects are briefly presented in this section. More information can be found in the project documentation [7]. A. Defining system boundaries and requirements The system can be presented as shown in Figure 6. The center represents the system itself as a link between the flower auction, airport and railway. The system can be divided into two subsystems; terminals and transport. The transport system focuses on the actual transport of cargo between terminals. The terminals form the link between the transport system and the various clients. Airport Flower Auction Material Handling Aircargo Air Transport Transport Material Handling Railcargo Railway station Rail Transport Figure 5. Overview of the area. The project started with a feasibility scan, which was completed in January The general conclusion was that an could make an important contribution to improving the accessibility of the Schiphol area and reducing the pressure on the environment. The next phase, the definition phase, was completed in January This introduced some financial and technical transparency. The findings of the feasibility scan were also examined and the first steps needed for the design phase were taken. The preliminary design phase was completed in Several concepts were generated for vehicles, material handling, routing/infrastructure, terminal layout and control. Currently a lot of testing is being done on the different prototypes. The designing of the transportation system and Figure 6. The system. As the system must live up to the expectations and objectives of those who will eventually use it, functional requirements are formulated. A difficulty with these new forms of transport is that it is unclear who the users will be in say 2020, which makes it difficult to determine what the users will require in Some of the functions that the must fulfill are already clear and are described in the project documentation [7]. B. Type of cargo and prognosis Several types of cargo must be transported by the varying from smaller Euro pallets and boxes to flower carts and the larger Unit Load Devices use for air transportation. Figure 7 gives an impression of several different types of cargo to be transported with the.

4 Airmodule Flower carts Aircraft pallet DTM vehicle Rubber tyred AGV, self guidance in tube (wheels on tube surface) electronic guidance on terminal Front-wheel steering One side loading AC electric drive Battery powered Figure 7. Different types of cargo to be transported. A transport unit was defined based on the largest load to handle. This TRE, as it is called, has the same length and width as a 10-ft. main deck Aircraft pallet (3180*2440 mm). A TRE can consist of one 10-ft. aircraft pallet, six regular pallets or Airmodules or 4 auction carts. By using the transport unit, the Tons per Year can be translated into TRE per Year as presented in table 1. These figures can be used for the simulations and dimensioning of the system. to Schiphol Hoofddorp Aalsmeer from Schiphol Hoofddorp Aalsmeer Table 1. Prognosis of transport volumes in thousands of TRE per year in C. Method of transport When designing a transportation system the method of transportation is usually one of the first aspects to be considered. Three vehicle concepts were developed for the -ASH project. The general vehicle specification, for all three concepts, stated that: - All types of cargo mentioned above must be transported. - The vehicles must be fully automated and be free ranging on terminals. - The drive must be electric. - The vehicles must be able to travel at 6 m/s, manage slopes up to 12 %, accelerate with 1 m/s 2 and decelerate with 2 m/s 2. The three vehicle concepts are presented below each with their own characteristics. Spykstaal vehicle Rubber tyred AGV with full electronic guidance Front-wheel steering Front and side loading DC electric drive Battery powered D. Material handling Different material-handling concepts have been considered for loading and unloading the vehicles. Four main concepts were created by combining two main choices. The cargo can be lifted or rolled it in and out of the vehicle and the use of slave pallets can also be considered instead of handling all different types of cargo separate. Figure 8 gives an impression of four different material handling concepts. Rolling cargo & use of slave pallets Rolling cargo & separate cargo handling Figure 8. Material handling concepts Lifting cargo & use of slave pallet Lifting cargo & separate cargo handling E. and system layouts By combining concepts for vehicles and material-handling and generating different docking concepts and track layouts as building blocks, it is possible to create different terminal concepts. Figure 9 present one of the many terminal concepts created. Lödige vehicle Rail mounted AGV in tunnel and rubber tyred electronic guided on terminal Four-wheel steering Two Side loading AC electric drive Battery powered on terminal and power rail in the tunnel Figure 9. concept for the flower auction.

5 This terminal, developed for the flower auction in Aalsmeer, is one of the larger terminals and is located on ground level. The vehicles enter the terminal via a slope. At the terminals the automated free ranging vehicles drive on a circulation track and can load or unload at several docks. After loading or unloading the vehicle re-enters the circulation track and can leave the terminal or park on one of the parallel parking places in the center of the terminal. Many different routes and terminal locations have been proposed during the course of the project. The layout of the system depends on many factors like the location of the different areas to be connected and the distances and obstacles between them. The number, location and orientation of the terminals in the different areas also influence the routing of the system. Figure 5 presented one of the original system layouts with one rail terminal near Hoofddorp (top left), three terminals at Schiphol (top right) and one large terminal at the Flower auction in Aalsmeer (bottom right). F. Control and information system The proposed architecture for the control system is presented in Figure 10. LOCES, at the top of the hierarchy, is the logistical control module that generates transport orders. TRACES is the traffic control module which coordinates the movements of the vehicles, thus preventing conflicting use of infrastructure. The control of the physical equipment itself is shown at the bottom of the figure and is not part of the overall control system, but rather a control unit developed by the equipment manufacturer in accordance with clearly defined interfaces. amount of equipment installed in the tunnels must also be minimized. This requires an operating system with autonomous vehicles only requiring incidental contact with the control system in critical areas, such as route changing points or terminals. For more information on the control system reference is made to [7][8] and [9]. G. Design status of the transportation system Several concepts were generated for vehicles, material handling, routing/infrastructure, terminal layout and control. Currently a lot of testing is being done on the different prototypes, which will be discussed in the next section. The results of the research, development and testing should present sufficient information and insight to specify the framework for the detailed engineering of the -ASH system. The planning and preparations for the final engineering and construction are now taking place. V. PROTOTYPING AND TESTING Developing large-scale transportation systems involves different kinds of prototyping and testing. Virtual prototyping, or computer simulation, is used to predict the performance and characteristic of a system or component that is yet to be built. Within the project computer simulations have been used not only to predict total system performance but also to predict separate vehicle behavior (vehicle dynamics). layouts have also been simulated to predict terminal performance and develop logistic control strategies. Figure 11 show two examples of this kind of virtual prototyping. System simulation Transit time distribution with different numbers of AGV s Loces Logistic Module actions Basic Server Actor events % delivered within time AGV's 350 AGV's 360 AGV's 380 AGV's Traces 0 Traffic control 0:00 0:15 0:30 0:45 1:00 1:15 1:30 1:45 2:00 Basic Process Time (hours) Control manoeuvres events simulation model with 8 docks (Flower auction) Physical Equipment Driver Equipment Figure 10. Proposed architecture for the control system A distributed control system using object oriented programming is proposed, providing a scalable system able to control the many vehicles (200 to 400) and make the different sections and terminals operate as independently as possible with as little communication as possible. In order to minimize the maintenance work in the tunnels, the Some simulation results: Dock performance (AGVs p.h) performance (operations p.h.) Time in terminal per AGV (min.) Distance driven in terminal (km) Number of accelerations >0.5 m/s Figure 11. Virtual prototyping on system en terminal level

6 Although virtual prototyping has become very important, it is still necessary to use a physical prototype of a vehicle or material-handling device to prove the feasibility of design and check the assumed characteristics used in the computer simulation. Three vehicle concepts and two material handling prototypes have been developed on a 1:1 scale and are tested at the TestSite [3][10]. Apart from physical 1:1 scale prototypes several smaller AGVs are used to test and develop the control system[7][8]. Figure 12 shows the 1:1 scale prototypes at the TestSite and presents a corner view of the whole site with some of the smaller AGVs carrying pallets (bottom right). On the top right the Lödige vehicle is shown next to a roller bed for rolling cargo on and of the vehicle. The Spykstaal vehicle, shown on the top left photo, uses the same roller bed for loading aircraft pallets sideways but can also handle carts through the front of the vehicle. On the bottom left a photo shows the DTM vehicle with a fork lifting device that loads the pallets through the right side of the vehicle. combining flows and connecting to a multi modal transport network. UFT can often be translated as Undisturbed Freight Transportation as the infrastructure does not always have to be underground. As construction cost are much lower above ground the feasibility of UFT systems increases. The -ASH project is considered to become the pilot project for UFT in the Netherlands, creating an undisturbed link between the flower auction in Aalsmeer, Schiphol airport and an international railway station near Hoofddorp. The -ASH project, starting in 1995, has generated know-how on designing automated underground freight transportation systems that can be used for future UFT projects. With the prototyping and testing sufficient information is gathered to specify the next two phases of the project, being the detailed engineering followed by the construction of the system. Figure 12 physical prototyping at the TestSite. The interaction between the different components such as the automatic loading and unloading of the vehicles is one of the critical elements in the automated transportation system and therefore one of the tests performed with 1:1 scale prototypes in the TestSite. Developing and testing the control system is one of the important activities performed at the TestSite. Other tests include driveline testing, vehicle dynamics and maneuvering at high speeds, positioning and maneuvering accuracy at low speed, robustness / FMEA and duration testing. VII. REFERENCES [1] Visser J.G.S.N. & Binsbergen A.J. Underground Logistical systems in cities: A visualization of the Future, ISUFT 2000 conference proceedings, Delft, September [2] Interdepartementale Projectgroep Ondergronds Transport -IPOT Transport onder ons: schakel in de keten, Den Haag [3] Pielage B.A., Design approach and prototyping of automated underground freight transportation systems in the Netherlands, ISUFT 2000 conference proceedings, Delft, September 2000 [4] Interdepartementale Projectgroep Ondergronds Transport -IPOT Transport onder ons: Van visie naar ralisatie (Eindrapport), Den Haag augustus [5] Bliss D., MailRail-70 years of automated underground freight transport, ISUFT 2000 conference proceedings, Delft, September [6] Rijsenbrij J.C., Automation: a process redesign, Europe Combined s, Rotterdam, October [7] Dunselman, J.R., Pielage, B.A., Rijsenbrij, J.C.(editors), Project Document of the Project: Transport Technology and Control System, Underground Logistic System ASH. TRAIL Research School / Connekt, Delft/Rotterdam [8] Verbraeck, Saanen & Valentin, Designing effective terminals and their control system for the Underground Logistic System Schiphol, ISUFT 2000 conference proceedings, Delft, September 2000 [9] Lindeijer D.G. & Evers J.J.M. TRACES The Agile traffic-control and engineering system, TRAIL Conference proceedings, TRAIL research School, Delft, December [10] Kusters L.J.J., Development of dedicated vehicles for tunnel transport systems ISUFT 2000 conference proceedings, Delft, September VI. GENERAL CONCLUSIONS In general one could state that UFT has potential in densely populated areas as it provides automated, undisturbed and reliable transportation and simultaneously reduces traffic and pollution above ground creating a better environment. The UFT studies in the Netherlands show that automated underground freight transportation systems could handle a considerable part of the domestic freight transport by