Tunnel Fire Suppression via Train Speed Reduction and Localized Water Mist
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Solution Overview
Problem
Current methods for fighting train fires in long railway tunnels are slow, allowing fires to reach full power and cause significant damage to both the train and infrastructure, due to the time required to access and extinguish the fire.
Innovation Solution
An installation with fixed and on-board fire detectors, strategically placed extinguishing stations, and a control unit that allows for rapid detection, slowing the train to a backup speed, and precise activation of high-pressure water mist extinguishing devices to localize and control the fire, minimizing water usage and infrastructure damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional fire fighting means are used (accessing burnt train through tunnel or service tunnel), then firefighters can reach the fire, but the intervention time is very long (about one hour) allowing fire to reach full power and cause significant damage
Solution Approach 1:
The patent implements preliminary action by pre-positioning extinguishing stations along the tunnel at strategic locations. When a fire is detected on a train, the system can immediately activate the nearest extinguishing station without requiring firefighters to travel through the tunnel. The control unit automatically identifies the fire location and activates the appropriate extinguishing devices, reducing intervention time from one hour to minutes while maintaining effective fire suppression capability.
2Object-affected harmful factors
If firefighters access the burnt train through the tunnel, then the fire can be extinguished, but the tunnel infrastructure suffers considerable damage and repair is long and difficult
Solution Approach 1:
The patent extracts the fire suppression function from the traditional firefighter-access model and implements it directly at the fire location through automated extinguishing stations. These stations are positioned along the tunnel and can independently suppress fires without requiring human intervention or tunnel access. This extraction of the suppression function to the point of fire origin prevents secondary damage to tunnel infrastructure and eliminates the need for difficult tunnel repairs.
3Reliability
If the tunnel is neutralized for fire fighting operations, then the fire can be addressed, but train circulation is partially or totally stopped
Solution Approach 1:
The patent implements self-service by equipping trains with onboard fire detection systems that automatically trigger the fire suppression process. When a fire is detected, the train's own detection system communicates with the tunnel control unit, which then activates the nearest extinguishing station. This self-service capability allows fire suppression to occur without requiring tunnel closure or disruption to train circulation, maintaining both fire safety and operational productivity.
4Measurement precision
If extinguishing devices are distributed over the length of the extinguishing station, then fire can be localized and treated, but the system complexity increases
Solution Approach 1:
The patent implements feedback through a centralized control unit that receives signals from multiple detection devices (flame detectors, smoke detectors, thermal cameras) positioned along the extinguishing station. The control unit processes this feedback information to precisely locate the fire, determines which extinguishing devices need activation, and coordinates their operation. This feedback-based control system achieves precise fire localization and targeted suppression while managing system complexity through centralized intelligence rather than distributed decision-making.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables quick fire suppression within minutes, preventing fire spread and reducing damage by localized intervention with minimal water consumption, effectively protecting the train and tunnel infrastructure.
Implementation Method 1
thanks to driving the train at the back-up speed then taking advantage of exceptional conditions to reduce the fire thanks to a mist of high-pressure extinguisher liquid and in particular a water mist
Implementation Method 2
devices for spraying an extinguishing liquid, these devices being individually controlled and distributed over the length of the extinguishing station
Implementation Method 3
The management of the volume of air flow in the railway tunnel following the start of the ventilation station (during the stopping phase of the train) expelling the smoke to protect the passengers of the train
Implementation Method 4
A control unit, connected to the fixed detectors (flame, smoke, CO) in the tunnel
Implementation Method 5
connected to the fixed detectors (temperature) of the station extinction to receive the in fire information
Data Source
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AI summary
The invention relates to equipment including fixed fire detectors (10) along the track (100) and fixed extinguishing stations (20) installed in the tunnel. Each station is provided with fire detectors (23) for locating the source, an automatic configuration system for targeting the area to be sprayed, individually controlled spraying devices (22), and a device for remotely or locally activating the spray. The station is preceded by a train stopping area (ZA) in which the train (TRO) starts a stopping sequence and slows down from the safety speed thereof to the zero speed thereof. A control center (30) manages the operation of the equipment and in particular orders a reduction of the train (TRO) running speed when the detectors (10) have detected a fire (flames, smoke, CO). The reduced speed (safety speed (Vs)) enables the train (TRO) to run as quickly as possible while mitigating the progression of the fire.