Victoria Line Research Articles

An evaluation framework for operational interventions on urban mass public transport during a pandemic

Decision making in a rapidly changing context, such as the development and progression of a pandemic, requires a dynamic assessment of multiple variable and competing factors. Seemingly beneficial courses of action can rapidly fail to deliver a positive outcome as the context changes. In this paper, we present a flexible data-driven agent-based simulation framework that considers multiple outcome criteria to increase opportunities for safe mobility and economic interactions on urban transit networks while reducing the potential for Covid-19 contagion in a dynamic setting. Using a case study of the Victoria line on the London Underground, we model a number of operational interventions with varied demand levels and social distancing constraints including: alterations to train headways, dwell times, signalling schemes, and train paths. Our model demonstrates that substantial performance gains ranging from 12.3–195.7% can be achieved in metro service provision when comparing the best performing operational scheme and headway with those realised on the Victoria line during the pandemic.

Hemagglutinin Antibodies in the Polish Population during the 2019/2020 Epidemic Season.

The aim of the study was to determine the level of antibodies against hemagglutinin of influenza viruses in the serum of subjects belonging to seven different age groups in the 2019/2020 epidemic season. The level of anti-hemagglutinin antibodies was tested using the hemagglutination inhibition (HAI) test. The tests included 700 sera from all over Poland. Their results confirmed the presence of antibodies against the following influenza virus antigens: A/Brisbane/02/2018 (H1N1)pdm09 (48% of samples), A/Kansas/14/2017/ (H3N2) (74% of samples), B/Colorado/06/ 2017 Victoria line (26% of samples), and B/Phuket/3073/2013 Yamagata line (63% of samples). The level of antibodies against hemagglutinin varied between the age groups. The highest average (geometric mean) antibody titer (68.0) and the highest response rate (62%) were found for the strain A/Kansas/14/2017/ (H3N2). During the epidemic season in Poland, only 4.4% of the population was vaccinated.

A new method to derive rail roughness from axle-box vibration accounting for track stiffness variations and wheel-to-wheel coupling

Railways require frequent inspection to maintain acceptable levels of rail roughness. Accelerometers mounted on in-service railway vehicles potentially offer a cost-effective method of near-continuous roughness monitoring by using a transfer function in the frequency domain to derive rail roughness spectra from measurements of axle-box vibration. This paper addresses two phenomena that currently limit the effectiveness of such a method: the variation in track support stiffness along the track, which is the least known property of the vehicle-track system, resulting in a variable transfer function; and the vibration coupling between wheels, which limits the effectiveness of a transfer function based on a single wheel. A new method is presented that estimates the track stiffness by curve-fitting a transfer function to the peak in the axle-box acceleration spectrum associated with the so-called ‘P2’ resonance of the wheel-rail system. Wheel-to-wheel coupling is addressed by refining the transfer function to account for multiple wheels running on the same rail. Axle-box acceleration is also affected by wheel roughness, and the use of a comb filter is briefly demonstrated to mitigate this effect. The developments are evaluated by both numerical simulation and measurement trials conducted on London Underground’s Victoria line.

Multi-agent deep reinforcement learning for adaptive coordinated metro service operations with flexible train composition

This paper presents an adaptive control system for coordinated metro operations with flexible train composition by using a multi-agent deep reinforcement learning (MADRL) approach. The control problem is formulated as a Markov decision process (MDP) with multiple agents regulating different service lines in a metro network with passenger transfer. To ensure the overall computational effectiveness and stability of the control system, we adopt an actor–critic reinforcement learning framework in which each control agent is associated with a critic function for estimating future system states and an actor function deriving local operational decisions. The critics and actors in the MADRL are represented by multi-layer artificial neural networks (ANNs). A multi-agent deep deterministic policy gradient (MADDPG) algorithm is developed for training the actor and critic ANNs through successive simulated transitions over the entire metro network. The developed framework is tested with a real-world scenario in Bakerloo and Victoria Lines of London Underground, UK. Experiment results demonstrate that the proposed method can outperform previous centralized optimization and distributed control approaches in terms of solution quality and performance achieved. Further analysis shows the merits of MADRL for coordinated service regulation with flexible train composition. This study contributes to real-time coordinated metro network services with flexible train composition and advanced optimization techniques.

Train Dwell Time Efficiency Evaluation with Data Envelopment Analysis: Case Study of London Underground Victoria Line

Train dwell time is a complicated component and depends on many factors. One of the dominant factors is passenger volume. This study used actual train movement data and passenger demand data from London Underground, UK, to estimate the number of passengers and train dwell times at each station, and then evaluated train dwell times from a different perspective. Considering the various characteristics of stations, it is complicated to evaluate dwell time. Therefore, data envelopment analysis (DEA) was introduced to evaluate the dwell time at each station in relation to passenger volume at that station. The study investigated whether the dwell time spent at stations is efficient when considering the number of passengers that the stations can serve. The results showed that, in low-passenger-volume stations, the dwell time efficiency score is low and increases relative to the increase in passenger volume. For high-passenger-volume stations, interactions between passengers are more relevant and have a strong influence on dwell time. Passenger movement direction is a key factor to classify stations. This research proposes that stations should be classified according to their characteristics, and points out the challenge at any station with the same characteristics as Victoria station which has high passenger volume with bi-directional flow, and where trains arriving are crowded. This characteristic would result in high interactions between passengers, thus making a long dwell time. The station has to handle high passenger volume and also has to keep the dwell time within the threshold.

Adaptive Metro Service Schedule and Train Composition With a Proximal Policy Optimization Approach Based on Deep Reinforcement Learning

This paper presents an integrated metro service scheduling and train unit deployment with a proximal policy optimization approach based on the deep reinforcement learning framework. The optimization problem is formulated as a Markov decision process (MDP) subject to a set of operational constraints. To address the computational complexity, the value function and control policy are parameterized by artificial neural networks (ANNs) with which the operational constraints are incorporated through a devised mask scheme. A proximal policy optimization (PPO) approach is developed for training the ANNs via successive transition simulations. The optimization framework is implemented and tested on a real-world scenario configured with the Victoria Line of London Underground, UK. The results show that the performance of proposed methodology outperforms a set of selected evolutionary heuristics in terms of both solution quality and computational efficiency. Results illustrate the advantages of having flexible train composition in saving operational costs and reducing service irregularities. This study contributes to real time metro operations with limited resources and state-of-art optimization techniques.

Актуальность профилактики гриппа и пневмококковой инфекции в период продолжающейся пандемии COVID-19

The article discusses the issues of vaccine prevention of influenza and pneumococcal infections during the ongoing pandemic of the new coronavirus infection COVID-19. Statistical data on the prevalence of these infections at the current time are provided. Co-infection can increase the symptoms of the diseases in these cases, and managing this condition is important for certain groups of patients. Respiratory viruses induce the attachment of pneumococcus, Pseudomonas aeruginosa and Hemophilus bacillus to the epithelial cells of the respiratory tract. The WHO position on influenza vaccination in the context of the COVID-19 pandemic is presented, and its main provisions are analyzed. Recommendations on the use of the main types of vaccines are given. Currently, the priority is to use 4-valent vaccines that ensure the development of the most stable immunity. In the Russian Federation, such a vaccine that meets all WHO recommendations is Ultrix Quadri, a tetravalent inactivated split influenza vaccine. The drug is a mixture of protective surface and internal antigens of influenza viruses of type A [subtypes A(H1N1) and A(H3N2)] and type B (Yamagata line and Victoria line). The use of vaccination schemes for pneumococcal infection was also discussed.

An actor-critic deep reinforcement learning approach for metro train scheduling with rolling stock circulation under stochastic demand

This paper presents a novel actor-critic deep reinforcement learning approach for metro train scheduling with circulation of limited rolling stock. The scheduling problem is modeled as a Markov decision process driven by stochastic passenger demand. As in most dynamic optimization problems, the complexity of the scheduling process grows exponentially with the amount of states, decisions, and uncertainties involved. This study aims to address this ‘curses of dimensionality’ issue by adopting an actor-critic deep reinforcement learning solution framework. The framework simplifies the evaluation and searching process for potential optimal solutions by parameterizing the original state and decision spaces with the use of artificial neural networks. A deep deterministic policy gradient algorithm is developed for training the artificial neural networks via simulated system transitions before the actor-critic agent can be applied for online schedule control. The proposed approach is tested with a real-world scenario configured with data collected from the Victoria Line of London Underground, UK. Experiment results illustrate the advantages of the proposed method over a range of established meta-heuristics in terms of computing time, system efficiency, and robustness under different stochastic environments. This study innovates urban transit operations with state-of-the-art computer science and dynamic optimization techniques.

Noise Exposure on the London Underground, an Observational Study over a Decade.

There are no hearing protection regulations in place for passengers using public transport, such as the London Underground. In light of this, we sought to examine sound pressure levels experienced by regular users of the London Underground. Sound pressure levels (A-weighted decibels: dBA) were taken on moving London Underground carriages between Euston and South Wimbledon on the Northern Line, and between Euston and Vauxhall on the Victoria Line, during 2006 and 2018. In addition, carriage sound pressure levels travelling within Zone 1 of the London Underground were tested in 2019. Three experimental and three technical repeats were undertaken using a hand-held calibrated multi-function sound level meter. Passengers are routinely and consistently subjected to sound pressure levels exceeding 80 dBA, with levels sometimes reaching over 100 dBA. This study is unique within the literature, with no published studies outlining exposure levels for London Underground passengers. It provides evidence of elevated noise exposure to passengers, consistently along large stretches of the London Underground, over a prolonged study period (2006-2019). Sensorineural hearing losssound pressureexposureLondonundergroundtube. N/A Laryngoscope, 2020.

Features of Epidemic Process of Influenza and its Etiology in the Countries of the Northern and Southern Hemispheres in the Period of Circulation of Pandemic Virus A(H1N1)pdm09 (According to WHO)

Relevance. Influenza is characterized by global distribution and the difference in its seasonality in countries with temperate and tropical climates. The importance of studying antigenic variation of influenza viruses due to the fact that changes in the antigenic structure is an evolutionary mechanism of adaptation of the virus to ensure its survival and cause annual epidemics.Aims. The Aim of this study was to identify the peculiarities of the geographical spread of influenza (seasonal), etiology and the rate of antigenic variability of influenza viruses A and B.Materials and methods. Based on data from WHO Reference research centers, information was collected on circulating influenza virus strains from 1975 A(H3N2), 1977 A(H1N1)pdm09 and type B of the Yamagata and Victoria lines from 1987 to 2019, as well as data on the number of all identified influenza viruses and individual strains circulating in the Northern and Southern hemispheres from 2008 to 2018.Results and discussion. Analysis of the global spread of influenza, its etiology and antigenic variability of viruses, according to WHO, showed that the influenza A(H1N1)pdm09 virus was the main causative agent of epidemics and regional outbreaks in seasons of high influenza activity in all countries except the United States and Canada, where influenza A(H3N2) and B viruses dominated in countries with severe seasonality, the change of season led to a change in the etiology of influenza, and in tropical countries, the A(H1N1)pdm09 virus more often remained dominant in all seasons of the year.Conclusions. The pronounced seasonality of influenza in Northern countries and its absence in tropical countries, where regional outbreaks prevailed in all seasons of the year, were confirmed. Low antigenic variability of influenza A(H1N1)pdm09 strains was confirmed, and the highest – A(H3N2). Among influenza B strains in the Victoria line had less antigenic variability, because the duration of its circulation before the appearance of a new drift variant was longer than that of the Yamagata line. The tendency to increase the total duration of circulation of influenza viruses B/Victoria, A(H1N1)pdm09 and B/Yamagata due to increased circulation before the emergence of new drift variants is shown.

A rail network performance metric to capture passenger experience

For passenger rail operators worldwide a common concern is to better understand and improve passenger experience. Based on factors including train movement times and crowding, the Journey Time Metric and Disutility Metric can be used to quantitatively assess the journey experience of individual passengers. However an assessment of overall network performance is also desirable. This paper presents a whole-network assessment metric that captures passenger experience by aggregating and normalizing individual journey assessments. The newly developed metric is validated against customer satisfaction data measured in passenger surveys of the London Underground Limited Victoria Line with a statistically significant correlation (P < 0.005) between the predictions and the measurements. It is found that there is a high degree of correlation (ρ = 1.00, P < 0.005) between the network scores calculated using the new whole-network assessment metric with either the Journey Time Metric or Disutility Metric despite their different formulations and countries of origin. Through development of the new metric it is identified that many commonly used network assessment metrics (e.g. Public Performance Measure and the end-to-end journey time of passengers) are insensitive to crucial aspects of passenger experience. The newly developed metric could be used by rail operators to better select strategies for improving passenger experience.

Shallow high-resolution geophysical investigation along the western segment of the Victoria Lines Fault (island of Malta)

The Victoria Lines Fault (island of Malta) is a >15 km-long and N260°-striking segmented normal fault-system, which is probably inactive since the late Pliocene. In the westernmost part, the Fomm Ir-Rih segment displays comparable geologic throw and escarpment height (~150–170 m), moreover its hangingwall hosts thin patches of Middle Pleistocene clastic continental deposits (red beds), which are poorly preserved elsewhere. We acquired two seismic transects, by collecting ambient vibration recordings, processed by using horizontal-to-vertical spectral ratios, complemented by one high-resolution 2-D refraction tomography survey crossing this fault where it is locally covered by red beds and recent colluvial deposits.We found a resonance peak at ~1.0 Hz in the hangingwall block, whereas clear peaks in the range ~5.0–10.0 Hz appear when approaching the subsurface fault, and we relate them to the fractured bedrock within the fault zone.The best-fit tomographic model shows a relatively high-Vp shallow body (Vp 2200–2400 m/s) that we relate to the weathered top of the Miocene Upper Coralline Limestone Fm., bounded on both sides by low-Vp regions (<1400 m/s). The latter are the smeared images of steep fault zones. Tomography further reveals a thick (~15–20 m) low-Vp (<1000 m/s) zone, which could be a syn-tectonic wedge of colluvial deposits developed in the downthrown block. Surface waves analysis indicates lateral changes of the average shallow shear wave velocity, with Vs ~130 m/s within the inferred fault zone, and Vs >230 m/s above the weathered top-bedrock.Our results depict a clear seismic signature of the Victoria Lines Fault, characterized by low seismic velocity and high amplification of ground motion. We hypothesize that, during the Middle Pleistocene, faulting may have affected the basal part of the red beds, so that this part of the investigated complex fault-system may be considered inactive since ~0.6 Myr ago.

Development over London Underground tunnels: No. 1 Grafton Street

This paper describes a case history associated with the design of a building scheme at a site in Mayfair, London situated directly above the existing London Underground's Victoria Line tunnels. It confirms how this important constraint of the presence of the tunnels, influenced the design and how the railway protection measures were agreed and implemented. It explains the development of the feasibility scheme, the detailed design of a raft foundation solution, the retained façade scheme and the requirement to limit settlement, thus restricting the effect on the existing tunnels. It shows that predictions of heave due to demolition, and settlement due to construction, were assessed as realistic and compared favourably against actual monitoring results obtained during the works. The paper suggests ‘best practice' when achieving railway protection measures for building structure design and provides recommendations for future projects above existing tunnels.

Construction of the King's Cross northern ticket hall, London, UK

The recent completion of Network Rail's new western concourse at King's Cross station is the culmination of over 12 years of above and below ground station modernisation work that has transformed rail transport links in this part of north London, UK. The new concourse has been constructed directly above London Underground's northern ticket hall, which was the second and last phase of the redevelopment of its King's Cross St Pancras station. The construction of the northern ticket hall was a major undertaking and ultimately provided the support structure for the western concourse. The new ticket hall greatly enhances the overall capacity of the underground station and provides a second means of access to the Northern, Piccadilly and Victoria lines while also incorporating below ground links to both the King's Cross and St Pancras main line stations and to the enlarged Tube ticket hall. This paper describes the overall construction methodology of the main box forming the ticket hall with particular reference to the techniques used for bulk excavation, installation of plunge columns and the use of temporary propping.

Results of monitoring at the British Library excavation

The main phase of excavation for the basements of the British Library at St Pancras, London, was completed in 1987. The project included basements extending up to 25 m deep, through the London Clay and into the Lambeth Group. The excavations were formed using both the top-down method and open excavation with ground anchors. Existing major buildings lie within 25 m of the site and London Underground tunnels lie below and adjacent to the site. The purpose of this paper is to present the results of displacement monitoring; they are summarised in the paper and presented in more detail in online supplementary data files. The retaining walls advanced towards the site by up to about 32 mm and the clays expanded rapidly on unloading beneath the excavations, causing the Victoria Line tunnels to heave by up to 22 mm. The slow progress of the project provided an unusual opportunity to monitor ground and structure movements in the surroundings before site activity began. Ironically, it was found that the largest settlements of adjacent buildings were caused by the installation of equipment intended to measure the settlements. Extensive condition surveys were carried out, but no damage to adjacent structures or tunnels has been recorded.

The start of the line [lean manufacturing techniques

THERE CAN BE NO more graphic example of the cyclical nature of manufacturing than the experiences of Bombardier Trains. Its Derby manufacturing facility is currently manufacturing more trains per week than has ever been produced in its history. Production at the site is centred around three products: the Movia metro cars for the Victoria and Subsurface Lines (SSL), Class 379 Electrostars for National Express East Anglia and Class 172 Turbostars for Chiltern and London Midland. Whilst production is currently at a peak, all but the SSL contract will be complete by the end of the year, so Bombardier is seeking to secure more work for the site. It eagerly awaits pending announcements about key UK rail projects.

Squeezing the heat out of London's Tube

London Underground is planning to boost passenger capacity by increasing the number and size of its ‘Tube’ trains. However, on deeper parts of the network this will inject yet more heat into an already warm, subterranean environment which, combined with warmer weather, means cooling is now an essential part of upgrading works. This paper describes the challenges and proposed solutions for cooling the Victoria line, including doubling exhaust airflow capacity and innovative groundwater-based cooling systems for major stations.

Facies analysis and palaeoenvironmental interpretation of the Late Oligocene Attard Member (Lower Coralline Limestone Formation), Malta

AbstractThe Oligocene represents a key interval during which coralline algae became dominant on carbonate ramps and luxuriant coral reefs emerged on a global scale. So far, few studies have considered the impact that these early reefs had on ramp development. Consequently, this study aimed at presenting a high‐resolution analysis of the Attard Member of the Lower Coralline Limestone Formation (Late Oligocene, Malta) in order to decipher the internal and external factors controlling the architecture of a typical Late Oligocene platform. Excellent exposures of the Lower Coralline Limestone Formation occurring along continuous outcrops adjacent to the Victoria Lines Fault reveal in detail the three‐dimensional distribution of the reef‐associated facies. A total of four sedimentary facies have been recognized and are grouped into two depositional environments that correspond to the inner and middle carbonate ramp. The inner ramp was characterized by a very high‐energy, shallow‐water setting, influenced by tide and wave processes. This setting passed downslope into an inner‐ramp depositional environment which was colonized by seagrass and interfingered with adjacent areas containing scattered corals. The middle ramp lithofacies were deposited in the oligophotic zone, the sediments being generated from combined in situ production and sediments swept from the shallower inner ramp by currents. Compositional characteristics and facies distributions of the Attard ramp are more similar to the Miocene ramps than to those of the Eocene. An important factor controlling this similarity may be the expansion of the seagrass colonization within the euphotic zone. This expansion may have commenced in the Late Oligocene and was associated with a concomitant reduction in the aerial extent of the larger benthonic foraminifera facies. Stacking‐pattern analysis shows that the depositional units (parasequences) at the study section are arranged into transgressive–regressive facies cycles. This cyclicity is superimposed on the overall regressive phase recorded by the Attard succession. Furthermore, a minor highstand (correlated with the Ru4/Ch1 sequence) and subsequent minor lowstand (Ch2 sequence) have been recognized. The biota assemblages of the Attard Member suggest that carbonate sedimentation took place in subtropical waters and oligotrophic to slightly mesotrophic conditions. The apparent low capacity of corals to form wave‐resistant reef structures is considered to have been a significant factor affecting substrate stability at this time. The resulting lack of resistant mid‐ramp reef frameworks left this zone exposed to wave and storm activity, thereby encouraging the widespread development of coralline algal associations dominated by rhodoliths.

Methods explained: Cost-benefi t analysis

The concept of cost-benefit analysis (CBA) originated in the United States in the 1930s where it was used to create a solution to problems of water provision. The process arrived in the UK in the 1960s for use in the transportation sector, where it was applied to the construction of the M1 motorway and the Victoria Line on the London Underground. In recent years, CBA has found a new home in environmental policy, where there is increasing pressure to make informed policy decisions which take account of long-term costs and benefits. This article aims to explain the principles and methods behind CBA in a concise, introductory manner.

KR24 Use of QRA in Supporting a System Safety Case for the Victoria Line Upgrade

AbstractIn the support of a safety case for a complex system, there is often the need to gain an understanding of the overall risk for the system and the way in which this risk will change. To do this in quantitative terms requires a system quantitative risk model. There are a number of such models available for use in the UK railway domain: for heavy rail, the Railway Safety and Standards board (RSSB) has developed a Safety Risk Model (SRM) which is available to stakeholders, and for the London Underground (LU), a London Underground QRA model (LU QRA) has been developed for each underground line which can be used in support of safety cases.This paper describes the use of the LU QRA in supporting the safety case for the Victoria Line Upgrade (VLU), which involved an upgrade to rolling stock and signalling systems. It describes the primary uses of the model, the main issues involved and the techniques developed in the course of the task.