What is the purpose of a crossover?
It allows a train movement to go from one tunnel to another
How far apart are CP's?
What is the battery life for the battery back up for the permanent lighting?
What is a PRD and how far apart are they?
How would you open a CP from a running tunnel?
- by hand (hand wheel)
- Calling the RCC
- Pressing the mushroom button
Approximately how long are the running tunnels?
If you are travelling form the UK to France, what tunnel are you in?
Tunnel 2, North
If you are travelling from France to the UK, what tunnel are you in?
Tunnel 1, South
What are the three main functions of the service tunnel?
- A safe haven for the evacuation of passengers if necessary. The air pressure being higher than that of the running tunnels prevents the entry of some and fumes.
- Allows ventilation of the running tunnels via ADU.
- Provides access for personnel to compete planned and unplanned maintenance and also as means of an entrance in case of an emergency.
What is the purpose of a PRD?
- To relieve the air pressure buildup in front of a moving train, pushing it into an adjacent running tunnel. Also this reduces aerodynamic drag.
- To give aerodynamic protection in a given place in the tunnel.
- To prevent smoke from passing from one tunnel to another in the event of a fire.
How many crossovers are there?
- 1/3 and 2/3 distance into the tunnel
What are the two lighting systems running in the tunnel?
- Permanent - consists of illuminated direction signs every 75m.
- Main - when energised lights up 2250m of tunnel in 3x 750m sections in both service and running tunnel.
How is the main lighting switched on?
- By calling the RCC
- by pushing mushroom buttons located at the permanent lighting markers.
What is the NVS?
Normal ventilation system, This is used to keep the pressure in the service tunnel higher than in the running tunnels. This therefore prevents smoke or harmful gasses entering from the running tunnels. It also provides fresh air and ventilation to the running tunnels via the ADU's.
What is SVS?
Supplementary ventilation system, this is used in the event of an emergency and can move smoke and gases away from any given point by blowing or sucking out air via fans at each end of the tunnel at, sangatte and shakespear cliffe. It can also keep smoke or gas in one place if needed.
How are the tunnels maintained at a constant temperature and what is it?
- By 2 cooling pipes that run the length of the running tunnels filled with cold water.
- 30 degrees
Name two types of fire detection equipment and what are they?
- Flame detection
- smoke detection
- Flame detection is done by means of IR or UV. Uv is sensitive to electrical discharge (catenary flashes)
- Smoke detection is done by, Ionisation, which covers a full range of smoke particles via air sampling.
- Smoke detection is also done by scattered light detection, using light particles directed to a detector it senses if there is any change in the particles.
How many detection stations per running tunnel?
What is an LFDU?
- Local fire detection unit; an LED display which will show:
- first stage alarms (single detection)
- second stage alarm (double detection)
- location of alarm
- halon discharge (for equipment rooms)
What distance apart are the fire hydrants in the running tunnels?
What are the intervals in both the FR and uk tunnels?
- 2,4,6 in RT 2 north
- 1,3,5 in RT 1 south