Manage Successful Brownfield Applications

2018 ◽  
Author(s):  
Jian Sun ◽  
Kevin Blostic
Keyword(s):  
Mixed Mode ◽  
System Capacity ◽  
Signaling System ◽  
Maintenance Costs ◽  
Signaling Systems ◽  
Train Control ◽  
Operation And Maintenance ◽  
Track Circuit ◽  
Railroad Applications ◽  
New System

This paper provides a unique perspective on successful brownfield railroad applications. It presents realistic challenges and solutions when applying a turnkey solution with a replacement or an overlay system. Brownfield commissioning takes place when an existing infrastructure is to upgrade to a new system with a different technology than the incumbent one. As signaling systems are getting more and more complex, it is extremely important to maintain robustness in the system design as well as project execution, such as logistics, documentation, and issue reporting. Many transportation authorities are moving from their current train control signaling system to a new system to combat obsolescence issues, to gain better system capacity, and to lower operation and maintenance costs. This paper discusses brownfield commissioning in general, and also presents specific cases in migration from a track circuit interlocking system to a Communications Based Train Control (CBTC) system. These two systems have distinct characteristics that provide opportunities of coexistence, but also introduce difficulties in mixed-mode operations.

The Creation of Cab Signaling

2019 ◽  
Author(s):  
John Hofbauer
Keyword(s):  
The United States ◽  
Light Rail ◽  
Signaling System ◽  
Signaling Systems ◽  
Train Control ◽  
North East ◽  
The North ◽  
Rail Systems ◽  
The Us ◽  
Pennsylvania Railroad

Cab signaling enforces the separation between trains as well as enforcing trains to reduce speed as the train approaches signals displaying STOP. Cab signaling allow for and provides a safe way to eliminate the number of wayside automatic signals while the number of controlled speeds can be increased. Light Rail Transit (LRT) systems today are built completely with cab signaling and only fixed wayside signals are placed at interlockings for routing information. Experimental cab signaling systems began in the United States in the 1920s, kicked off by the Interstate Commerce Commission (ICC) ruling that required some form of Automatic Train Control (ATC) be installed on one passenger division by 1925. This paper will begin with examining the initial ATC designs (intermediate and continuous), the first experimental installations, the testing challenges and the overall enhancements that pioneered cab signaling systems in the US. The focus will include the teaming of the Pennsylvania Railroad with Union Switch and Signal (US&S) to develop, build and successfully test the continuous cab signaling system which later became the de facto standard. The early systems implemented used two (2) speeds, methods on adding a third speed and how the system became integrated with the existing automatic block signaling. How Pennsylvania Railroad (currently Amtrak) is still using the technology that started 100 years ago on the North East Corridor. It will also introduce how Light Rail systems operate on speed commands using cab codes.

Origins and Current Status of the Different Communications-Based Train Control Products

2020 ◽  
Author(s):  
Kenneth Diemunsch ◽  
Nagaratnam Rabindran
Keyword(s):  
Traffic Control ◽  
Access Point ◽  
Current Status ◽  
Maintenance Cost ◽  
Signaling System ◽  
Large Cities ◽  
Signaling Systems ◽  
Train Control ◽  
Transit Agencies ◽  
Diagnostic Capabilities

Abstract Communications-Based Train Control (CBTC) technology is used by transit agencies in large cities to maximize the use of their infrastructure. In comparison with conventional block signal system and cab signaling system, CBTC provides the most efficient capabilities with respect to headway and throughput while being the most economical in terms of maintenance cost [1]. CBTC also provides better diagnostic capabilities compared to traditional signaling systems. It uses limited number of equipment on the trackside compared to traditional signaling systems and allows either a centralized architecture or distributed architecture. For these reasons, CBTC is now the favored system for new lines as well as most signaling system renewals.[1] Despite widely used CBTC standards, the signaling industry is not in agreement regarding what qualifies as a CBTC system and which projects are the first “real” CBTC projects. This work describes the different CBTC vendors, their genesis, when access point based radio was first introduced (access point based radio is also referred by signaling engineers as free space propagation radio), the different consolidations with other CBTC companies, and their major projects. From the authors’ viewpoint, it is appropriate to present the CBTC vendors by geographical areas, for instance in North America: Bombardier Transportation, Thales Rail Signaling Solutions, in Europe: Alstom Transport, Hitachi Rail, Siemens Mobility, in Asia: Beijing Traffic Control Technology, China Railway Signal and Communications, Mitsubishi Electric Corporation, and Nippon Signals.

Consequences of Failed Track Circuits on Conventional Signaling System in CBTC Projects

2013 ◽  
Author(s):  
Kenneth M. Diemunsch ◽  
Daniel J. Reitz
Keyword(s):  
Signaling System ◽  
Train Control ◽  
Backup System ◽  
Train Operation ◽  
Track Circuits ◽  
Track Circuit ◽  
Transit Agencies ◽  
The Relationship ◽  
Multiple Scenarios ◽  
Rapid Mass

In recent years, many rapid mass transit agencies have chosen Communication Based Train Control (CBTC) technology to refurbish their signaling system or to equip a new line. CBTC technology is a type of Automatic Train Control (ATC) that allows transit agencies to increase nominal throughput and to improve safety. The main functions of CBTC are described in [1.] and [2.]. This technology can operate without fixed wayside track detectors such as track circuits. However, track circuit equipment continues to be implemented on the tracks and in the equipment rooms. For authorities under the Federal Railroad Administration, current regulations require use of track circuit but the main functional reason is to have a backup system in case of CBTC failure. Most transit agencies decide to include track circuit occupied and vacant status into the CBTC system in order to enhance safety. How to enhance safety and keep train operation efficient during track circuit failure is a challenge for CBTC projects. This paper discusses the relationship between the CBTC and the conventional interlocking system when track circuit failure occurs. The analysis in this paper applies to both relay and solid state interlocking systems as both technologies have to deal with the same impact under this scenario. The method of detection of track circuit failure by the CBTC system and the possible restrictions on CBTC train operation are not presented. The paper focuses on the interface between the CBTC and the signaling system. It begins by introducing the different types of track circuit failures and their consequences on conventional signaling system to address and compare multiple scenarios. Then, the paper discusses how the CBTC system can affect the conventional signaling system equipment, such as signals and train stops, once it has detected a track circuit failure. Transit agencies’ different possible approaches to manage track circuits failures within the context of an operating CBTC system are explained.

Evolutions in Railway Signaling: A “New Age” of Control?

2009 ◽  
Author(s):  
Cameron Fraser
Keyword(s):  
New Age ◽  
Safe Distance ◽  
Signaling Systems ◽  
Train Control ◽  
Train Routing

The development of railroad signaling systems evolved with the need to provide interlocking between points and signals, and block working to keep trains a safe distance apart. Accordingly, the archetypal behavior of train control is summed up as providing (1) safe and efficient train movement by (2) the management of train routing and separation. This has been rudimentary since the advent of railway signaling and propagated in even the most contemporary of technologies today.

Statistical Safe Braking Analysis

2011 ◽  
Author(s):  
David F. Thurston
Keyword(s):  
Control Systems ◽  
System Capacity ◽  
Worst Case ◽  
Stopping Distance ◽  
Train Control ◽  
Classic Theory ◽  
Braking Distance ◽  
Prime Determinant ◽  
Worst Case Approach

The main objective in optimizing train control is to eliminate the waist associated with classical design where train separation is determined through the use of “worst case” assumptions that are invariant to the system. In fact, the worst case approach has been in place since the beginning of train control systems. Worst case takes the most conservative approach to the determination of train stopping distance, which is the basis for design of virtually all train control. This leads to stopping distances that could be far more that actually required under the circumstances at the time the train is attempting to brake. Modern train control systems are designed to separate trains in order to provide safety of operation while increasing throughput. Calculations for the minimum distance that separates trains have traditionally been based on the sum of a series of worst case scenarios. The implication was that no train could ever exceed this distance in stopping. This distance is called Safe Braking Distance (SBD). SBD has always been calculated by static parameters that were assumed to be invariant. This is, however, not the case. Parameters such as adhesion, acceleration, weight, and reaction vary over time, location or velocity. Since the worst case is always used in the calculation, inefficiencies result in this methodology which causes degradation in capacity and throughput. This is also true when mixed traffic with different stopping characteristics are present at the same time. The classic theory in train control utilizes a SBD model to describe the characteristics of a stopping train. Since knowledge of these conditions is not known, poor conditions are assumed. A new concept in train control utilizes statistical analysis and estimation to provide knowledge of the conditions. Trains operating along the line utilize these techniques to understand inputs into their SBD calculation. This provides for a SBD calculation on board the train that is the shortest possible that maintains the required level of safety. The new SBD is a prime determinant in systems capacity. Therefore by optimizing SBD as describes, system capacity is also optimized. The system continuously adjusts to changing conditions.

scholarly journals OPTIMALITY OF CONTROL LIMIT MAINTENANCE POLICIES UNDER NONSTATIONARY DETERIORATION

1999 ◽  
Vol 13 (1) ◽  
pp. 55-70 ◽  
Author(s):  
Zvi Benyamini ◽  
Uri Yechiali
Keyword(s):  
Optimal Policy ◽  
Transition Probabilities ◽  
Stationary Problem ◽  
Control Limit ◽  
Maintenance Costs ◽  
Operation And Maintenance ◽  
Deterioration Process ◽  
Maintenance Policies ◽  
Deteriorating Systems ◽  
Limit Form

Control limit type policies are widely discussed in the literature, particularly regarding the maintenance of deteriorating systems. Previous studies deal mainly with stationary deterioration processes, where costs and transition probabilities depend only on the state of the system, regardless of its cumulative age. In this paper, we consider a nonstationary deterioration process, in which operation and maintenance costs, as well as transition probabilities “deteriorate” with both the system's state and its cumulative age. We discuss conditions under which control limit policies are optimal for such processes and compare them with those used in the analysis of stationary models.Two maintenance models are examined: in the first (as in the majority of classic studies), the only maintenance action allowed is the replacement of the system by a new one. In this case, we show that the nonstationary results are direct generalizations of their counterparts in stationary models. We propose an efficient algorithm for finding the optimal policy, utilizing its control limit form. In the second model we also allow for repairs to better states (without changing the age). In this case, the optimal policy is shown to have the form of a 3-way control limit rule. However, conditions analogous to those used in the stationary problem do not suffice, so additional, more restrictive ones are suggested and discussed.

scholarly journals Lessons from Photoreceptors: Turning Off G-Protein Signaling in Living Cells

Physiology ◽  
2010 ◽  
Vol 25 (2) ◽  
pp. 72-84 ◽  
Author(s):  
Marie E. Burns ◽  
Edward N. Pugh
Keyword(s):  
G Protein ◽  
Living Cells ◽  
G Protein Signaling ◽  
Protein Signaling ◽  
Signaling System ◽  
Signaling Systems ◽  
Recent Advances ◽  
Retinal Rods

Phototransduction in retinal rods is one of the most extensively studied G-protein signaling systems. In recent years, our understanding of the biochemical steps that regulate the deactivation of the rod's response to light has greatly improved. Here, we summarize recent advances and highlight some of the remaining puzzles in this model signaling system.

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