Criteria for Level Crossing Removal Risk Evaluation and Cost-benefit Analysis
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CRITERIA FOR LEVEL CROSSING REMOVAL RISK EVALUATION AND COST-BENEFIT ANALYSISLuis Ubalde Civil Engineer Adrina Bachiller Civil Engineer Carles Casas Civil Engineer
Email Contact: [email protected] CENIT (Centre for Innovation in Transport) UPC Technical University of Catalonia (Barcelona, Spain)
Key words cost-benefit effects FMEA rule stakeholders
ABSTRACT Nowadays, most railway accidents are due to the existence of level crossings. This fact involves important investments in order to reduce the risk associated to this part of the infrastructure. Despite these efforts, the design of a great deal of current level crossings is still inefficient to avoid road vehicle crashes and especially pedestrian severe accidents, which suppose social, political, economic consequences. Moreover, increased speed process in railways entails incompatibility with safety conditions. For instance, in Spain general rules applied to transport consider that top speed in lines where there are level crossings is about 160 km/h and then upgrading these lines compels undoubtedly level crossing removal campaigns. Therefore, the project of improved safety for road users and pedestrians, and increased speed in railways has to be channelled into risk evaluation using specific methods. One of these is FMEA (Failure Mode and Effect Analysis), which is based on calculating probability, severity and detection capability for whatever possible mode of accident. If this method indicated an excessive dangerousness, it would be necessary to remove the level crossing and made a cost-benefit analysis that took into consideration not only the direct effects but also all the stakeholders and effects (including external effects) involved in that case. The aim of this paper consists of describing how to use FMEA method for level crossing evaluation and how to use a complete cost-benefit analysis in order to know how much social profitability a removal campaign supposes.
1. INTRODUCTION In general, level crossings constitute currently one of the most dangerous issues of a railways line. Increased traffic and the fact that nowadays train speed is very higher than in the past (when most of the existing level crossings were designed) have led to promote level crossing removal campaigns or even to change regulations in order to avoid level crossings under certain circumstances. Modern trains are also more silent, which supposes extreme risk for pedestrians. Their decision of crossing is usually based not on looking at the track but on listening to any sound from a train. In case the engine driver does not use properly the claxon of the machine, presence of the train is not perceived in time by pedestrians. This situation is extremely important in stations or in level crossings with a relevant pedestrian traffic (typical case in urban areas). In this context, it is very important to analyse separately risks for road traffic and risks for pedestrians. Unfortunately, there are great deals of level crossings that have been designed exclusively for vehicles but both vehicles and pedestrians use them. Certainly, an accurate risk analysis can detect these cases, allowing defining solutions for minimizing dangerousness. Another case that deserves special attention is level crossing between platforms. Very often they are not signalized adequately. A specific risk analysis is required, considering not only ideal passengers in optimum form but also passengers with reduced mobility. Sometimes, an unfenced line involves uncontrolled level crossings along the track, especially near stations. Pedestrians like accessing to the station following the shortest way, which could be a very risky access if it is not signalised adequately. Most pedestrians are not conscious of the fact that trains are very silent nowadays and generate an air turbulence pulling to themselves, when circulating fast. Under these circumstances, legal rules are more and more strict, insisting on improved protection measures. However, regarding some aspects, on one hand, these rules are not enough in order to guarantee safety conditions and, on the other hand, reality is very different from what legal documents state.
2. CURRENT LEGAL SITUATION AND LEVEL CROSSING STATISTICS IN SPAIN 2.1. Statistics of accidents Despite the downward trend of the last decade, as you can see in figure 1, deaths associated to level crossings are not negligible in Spain. Rate between deaths and accidents is relatively high (63% on average) in comparison with accidents of different nature.
STATISTICS OF LEVEL CROSSING ACCIDENTS 80 70 60 50 40 30 20 10 0 1987 Accidents Deaths Injured people
Figure 1.- Statistics of level crossing accidents in Spain, including national broad gauge network (RENFE) and national narrow gauge network (FEVE). Source: Spanish Government Ministerio de Fomento (Ministry responsible for public works), 2001 .
2.2. Level crossing rules and classification Level crossing removal projects are often associated to application of transport rules. These rules consider three general aspects to make a decision about elimination or improved protections: railway speed, traffic momentum and visibility at the level crossing (table 1).
Table 1.- Aspects about level crossing elimination or improved protections considered in Spanish transport rules. Source: CENIT (2004). Speed Traffic momentum (AT)In high speed lines or even in lines where top speed is higher than 160 km/h, level crossings are not allowed. Daily average number of road vehicles (A) Daily average number of trains (T)
Technical visibility: Dt: technical visibility distance of level crossing (m) Vm: maximum speed of railway (km/h) N: number of tracks
D t = 1,1Vm (6,25 + N )Real visibility:
Visibility (rate between technical visibility and real visibility)
5mDr: real visibility (you have to consider the shortest one of the four possible visibilities)
According to a rule stated in 2001 by the Ministerio de Fomento (Spanish Ministry responsible for public works) new level crossings are not allowed and existing ones have to be removed when railway top speed is equal to or higher than 160 km/h or when traffic momentum (defined in table 1) is equal to or higher than 1500 . This rule substitutes another one stated in 1990, which determined as limits 160 km/h and 24000 respectively . When a level crossing is possible, protection system (signalling, crossing gates) has to be adequate for characteristics of road traffic and railway traffic. In tables 2 and 3 you can see specifications of the above rule of 2001.
Table 2.- Classification of level crossings according Spanish regulations (2001) depending on protection system. Source: CENIT (2004). Railway RoadType of level crossing Whistle poster Traffic lights Crossing keeper Vertical fixed signalling Standard traffic lights Horizontal fixed signalling Traffic lights (2 red intermittent lights) Acoustic signalling Complete or partial crossing gates
A Yes No No Yes B Yes* Yes No Yes C Yes* Yes No Yes D Yes No Yes Yes E Yes* No Yes Yes F Yes No No Yes * Whistle posters can be removed if there is acoustic signalling.
No Yes No No No Optional
Yes Yes Yes Yes Yes No
No Yes Yes No Optional No
No Optional Optional No Optional No
No No Yes No Yes No
Table 3.- Classification of level crossings according Spanish regulations (2001) depending on traffic characteristics. Source: CENIT (2004).Type of level crossing A Brief description Location Out of stations Fixed signalling At stations Provisional Vm < 160 km/h, 1000 < AT < 1500, A < 100 B Traffic lights and fixed signalling Out of stations Vm < 160 km/h, AT < 1000, A >100 At stations Crossing gates, traffic lights and fixed signalling Train only can run if it has permission given by railway personnel Crossing gates and railway personnel at level crossing Out of stations At stations Out of stations At stations Provisional No Vm < 160 km/h, 1000 < AT 100 Vm < 160 km/h, but level crossing for pedestrians and livestock or private level crossings Vm < 40 km/h, 1000 < AT < 1500 Vm < 40 km/h, 1000 < AT < 1500 Traffic characteristics Vm < 160 km/h, AT < 1000, real visibility > technical visibility
Level crossing for pedestrians and livestock
As you can see in figure 2, the most dangerous level crossings (non-protected) are the most common in Spain (data of 2001). Apart of this fact, real situation worsens, if traffic is evaluated. Effectively, as figure 3 shows, there were 79 level crossings that had to be removed (in 2001 in RENFE network). They were not according with stated by the above rule of 1990. If you consider criteria of the current rule, which was approved in 2001, level crossings that had to be removed increase extremely.
LEVEL CROSSING CLASSIFICATION (2001)6000
0 Total Protected (crossing gates Non-protected (only fixed or traffic lights) signalling) Private level crossing
Figure 2.- Level crossing classification in Spain, including national broad gauge network (RENFE) and national narrow gauge network (FEVE). Source: Spanish Government Ministerio de Fomento (Ministry responsible for public works), 2001 . It is very important to take into consideration the fact that counter measures in order to reduce risk involve a substantial investment and indubitable require a certain period of time. As figure 4 indicates, investment per year in level crossings in Spain during the last decade has been higher than 20 million but years 1991, 1992, 1993 and 1995. This investment has allowe