Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
The second site, Duomo, is covered and has lighting so work can proceed regardless of the weather (see Figure 7). There are about 20 workers per shift, working from 6:00 a.m. to 11:00 p.m., Monday through Friday. The workers use shovels and pails and then small tools to scrape the dirt. The work at this site is expected to be finished by May 2004. Archaeologists are currently excavating ma- terial from the early period of the Roman Empire, the 1st century A.D. Remains of building columns are being discovered. There are also the remains of wells from later periods at this level. Rome When preparing for the construction of Line C, planners knew the underground would need to travel through the heart of the city. This area contains many historic monuments and buildings and ar- chaeological remains. A database was used to deter- mine the route that would cause the least disruption to archaeological sites and monuments. Because tunnels will be excavated underneath the archaeo- logical remains, the most impact to the remains will come from the construction of the stations. Approximately 18 months is set aside for an archae- ological excavation at a station site. This is to ensure due diligence in recovery of ancient artifacts and to reduce impacts on project schedule and cost. Milan In Milan, archaeological remains are usually found within 6 to 7 m of the surface. They do not have an impact on construction. SYSTEM OPERATIONS Operations Control Athens Lines 2 and 3 of the Athens metro system were de- signed to operate with a central supervisory control concept. Train operators utilize cab signals with auto- matic train protection (ATP). A supervisory system provides real time information to the control center, an interface for train control, and automatic train identi- fication. Upgrade of the system to fully automatic train operations (ATO) was envisioned as an option in the original design concept. The design and construction of the first expansion phase for Lines 2 and 3 has pro- vided the impetus to begin that process. New cars re- quired for the extensions will be ATO equipped, and an ATO retrofit program is underway for the existing fleet. The control center is located underground at a key station intersection. In the control center, each line has a contemporary operations console with train lo- cation and signal indications. The control center is designed to provide super- visory control and data acquisition (SCADA) for power, ventilation, and other subsystems. Radio and hard wire communication systems also support the control center, as well as extensive closed circuit television (CCTV) applications. CCTV is utilized to assist line operation managers, to provide customer assistance, and to support emergency security re- sponse management. The Line 3 extension to the airport will share the ROW with suburban rail and will be controlled by a new suburban rail system control center. In order for the metro to run on the suburban railway track, the trains must have dual electric traction power and sig- nal equipment. Seven such trains have been spe- cially ordered. At the airport, the metro and railway will have separate dedicated platforms because the dimensions of equipment do not permit joint platform operation. Unlike the rest of the system, where metro trains operate at a maximum speed of 80 km/hr, the metro trains on the suburban line will operate at 120 km/hr to be compatible with suburban railway speeds. The travel time from the airport to the city center will be 27 minutes, with a frequency of three trains per hour. Naples The operation of Line 1 in Naples is managed at a central control center. The current center is an in- 13 Figure 7 Duomo excavation site.
terim configuration, and plans are underway to consolidate the central control center for Line 1 with other lines, including Lines 2 and 6. Train movements are supervised from this center with full ATO capability. Train operators perform a su- pervisory function as trains enter ATO control areas. Fixed communication circuits monitor and control train movements. The center also main- tains full communication with train personnel and customers. As in Athens, power and ventilation systems are centrally monitored at the control center by a SCADA system. CCTV applications are also extensively deployed to assist the control center in operations, emergency response, and security. Command and supervisory functions are centrally supported by hard wire and wireless communication systems. Rome The train control systems planned for Line C in Rome will utilize audio frequency circuits and oper- ate with central ATO/ATP. Trains will also have an operator on board, as is the practice with Lines A and B. A road/vehicle management control center has been implemented in the city center of Rome. The team visited STAâs traffic control center to observe the ITS ROMA system in operation. The layout and activity of the control room had many similarities to rail operations centers (see Figure 8). Information at the center is collected from a dis- tributed system of 2,500 fixed roadway sensors and 60 strategically placed cameras. The cameras have the ability for remote field of vision manipulation to provide greater area coverage. These systems relay information over a fiber optic network, much of which is routed through metro tunnels. Real time traffic flow modifications are achieved through a distributed system of electronic message displays and zone control sensors that regulate vehicles by smart card permits. Improperly equipped vehicles that enter a controlled access point of a limited traf- fic zone are photographed, and the registered owner is fined. Key traffic signals are also aided by road sensor technology. Milan In Milan, train control for Lines 2 and 3 are ATO based with an operator in the cab. Line 1 utilizes a cab signal system with automatic stopping at sta- tions (see Figure 9). The two new lines under devel- opment are expected to be driverless. Train control is centralized in a contemporary control center. The control concept provides three major functional di- visions: train operations, station operations, and equipment/power supervision. Effective system communication belongs to a separate surface opera- tions center. Information technology supporting surface modes was also described to the team by ATM. Milanâs high degree of functionality in this area and its transit organizational structure has enabled ef- fective service coordination and enhanced customer information between rail and surface modes. The surface control center has the ability to track vehicle locations through a landmark-based system and col- lect data on vehicle status. In addition, vehicle condition/status data have numerous uses. For exam- 14 Figure 8 ITS Traffic Control Center managed by STA in Rome, Italy. Figure 9 Milanâs train operator console.
ple, real time statistics permit maintenance person- nel to intervene when selected performance toler- ance standards are exceeded and before customers are inconvenienced by a vehicle failure. Public ad- dress information may be dispatched centrally to the entire system or to an individual service or particu- lar vehicle. Customized announcements are usually entered into a computer console and simultaneously dispatched through a voice simulator. Voice simu- lation permits improved audio clarity, uniformity of communication, and automated multilanguage capability. Power Systems In Athens, traction power is handled by a dis- tributed system of rectifier installations providing 750 volts of direct current (VDC) under normal op- eration. These substations are supplied by the local power grid and are designed to provide substantial redundancy to protect them from local power out- rages. Rolling stock is equipped with regenera- tive braking systems for energy conservation. Emergency power cut-off switches are also located at regular intervals along the ROW. Power for tun- nel lighting, wayside equipment, and stations is pro- vided by separate power feeds controlled at stations. Critical systems are supported by power back-up equipment, generally in the form of increased sup- ply redundancy, battery backups (with a 2-hour re- serve capacity), and uninterrupted power supply (UPS) for data/control systems. In addition, electric companies in Athens are provided a separate room for transformers at certain stations. Traction power for Line 1 in Naples is distrib- uted by an overhead catenary system, thereby leav- ing the track bed more accessible for maintenance and emergency evacuation. Direct current (DC) power is fed by a distributed system of four rectifier- equipped substations. Separate power feeds supply equipment systems with a hierarchy of reserves and redundancy to ensure power to critical systems in the event of blackouts or local power interruption. Auxiliary power for selected systems includes UPS and/or diesel generators with up to 4 hours of re- serve capacity. In the event of a blackout, the Naples railway system is outfitted with a three-level power supply system. If this situation were to occur, the normal power supply would be automatically switched to a back-up supply source sufficient to operate the sys- tem. In the unlikely event of a failure of the back-up system, a diesel generator that is capable of operat- ing the system for up to 4 hours would provide power. In Rome, power distribution for Line C will em- ploy an overhead catenary system similar to the scheme utilized for Lines A and B. Power distribution systems for Lines 2 and 3 in Milan are catenary, while Line 1 has third-rail power distribution. Line 2 evolved as a catenary system be- cause a portion of the ROW was already utilized by a regional rail service utilizing overhead power. For Line 3, overhead power was selected as the opera- tional preference. Newer rail cars are equipped with alternating current (AC) propulsion and regenera- tive braking. Many older cars are being retrofitted with AC propulsion as part of a comprehensive overhaul. Finally, local generators are available to provide power back-up of critical systems. Ventilation and Lighting In Athens, routine ventilation of the system is achieved by the piston action of the train and sec- ondary fan equipment at stations. For Line 1 in Naples, ventilation channels equipped with large reversible fans are typically lo- cated about halfway between stations. During nor- mal operations, the ventilation system ensures suffi- cient air exchange to remove excess heat and create positive airflow, counteracting possible pressure changes due to train movements. Station lighting systems are typically linear, providing a raceway for other wiring and integration with signage compo- nents. Light wells for both natural lighting and ven- tilation are utilized in several locations. The mechanical ventilation system in Rome uti- lizes airshafts located between stations and air bal- ance shafts located at either end of the stations. Air ventilation systems are located above and below sta- tion platforms. Tunnel ventilation for Lines 1 and 2 in Milan is provided by a system of vent fans. Additional emer- gency ventilation capacity is provided on Line 3. Centralized control of power and ventilation sys- tems is supplied at the control center. Fare Structure The Athens metro system employs a self-en- forced open-type fare control concept. A customer 15
