Introduction Flashcards
At a very high level how can the UK rail industry can be divided into?
- Mainline network
- Underground railways
- Light rail and tramways
- Minor & heritage railways
How is the work of the rail industry legislatively shaped?
The work of the rail industry is shaped by UK and European legislation.
- UK legislation:
Railways Act, Health & Safety at Work Act, Railways Interoperability Regulations, + many more - EU legislation
Regulations concerning a European rail network for competitive freight, on the allocation of railway infrastructure capacity, the levying of charges for the use of railway infrastructure, and many more
What are the responsible governing bodies for the rail industry?
Government • Department for Transport • Transport for London • Additional bodies in Scotland and Wales • Office of Rail and Road
What are the responsible safety bodies for the rail industry?
- Rail Accident Investigation Branch – responsible for
investigating rail accidents. - Rail Safety and Standards Board – conducts research and
gives advice on safety & cross-industry issues
In what categories of companies does the UK industry divide itself into?
- Network Rail – the rail infrastructure owner and operator
- Train operating companies – operate passenger trains
- Freight operating companies – who operate freight trains
- Rolling stock companies – who own and lease trains to train operating companies
What are some areas that a consultant mechanical engineer might look at in projects within the rail industry?
EXAMPLES
- Fatigue of rail: predicting the life of rails
- Calculating energy use dependence on driving styles, speed, timetable
- Influence of welds in vehicle strength in a crash
- Noise and vibration: how the surface roughness of rails and wheels is converted into noise, and how loud this sounds to people
How many stations does the main UK rail network have?
2,500
How many miles are there in the UK?
20,000 miles of track
How many bridges and tunnels does the rail network have?
40,000 bridges and tunnels
Who owns and manages the rail track?
The track is owned and managed by Network Rail
How is the collaboration between track and vehicle companies facilitated?
Several “System Interface Committees” exist to help track and vehicle companies work together
What is the typical design life of passenger vehicles?
Design life of 30-35 years
[(Much greater lifetime and distances covered than equivalent road vehicles (either cars or buses)]
[Rough idea – Sheffield to London return (320 miles), twice a day, 330 days/year=211k-miles, 35 years=7.4 million miles]
What does the suspension of most UK passenger vehicles consist of?
Suspension consists of 4 axles per vehicle, mounted in pairs on bogies
How long are the typical single vehicles (coaches)?
Typically around 20-25m long
How much do single vehicles usually weigh?
Around 40 tonnes
Draw a diagram showing a bogie with its main parts
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Why use bogies? Draw a diagram to explain concept
- Geometry – to allow a long vehicle to move around a curve
- Without bogies – moving the wheels closer together fixes the problem, but makes the vehicle unstable.
- Without bogies – wheels very badly aligned, will fail to corner well and are likely to derail.
- Bogies – allow good support of the vehicle, and the ability of the wheels to align with curvature of the track.
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What is a wheel set?
Within a bogie there’s two ‘wheel sets’
2 wheels + axle = wheelset
Draw a wheel set
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Why are the wheels coned in opposite directions?
The wheels are ‘coned’ in opposite directions.
Linking them by an axle creates a self-aligning system which should run without flange contact.
The rails have a curved surface to create a ‘point’ contact.
Going around a corner the ‘outside’ wheel needs to roll further than the ‘inside’ wheel
The coning allows this to happen in a controlled way
What happens during steering?
- Going around a corner the ‘outside’ wheel needs to roll further than the ‘inside’ wheel
- The coning allows this to happen in a controlled way
- The wheelset shifts laterally, changing the radius of the wheel at the point of contact
- The larger (outside) and smaller (inside) radius enable the wheel-rail contact to stay close to pure rolling at both sides, and go around a corner
- Excess sliding in the contact leads to rail & wheel wear and consumes energy
Why do trains tilt?
Tilting trains are all about passenger comfort during cornering
The angle of the body doesn’t change the equations of circular motion
What is a cant?
‘Cant’ refers to the difference in height between low and high rails
Why is there sometimes a height difference between the two rails?
The height difference means a component of train weight is directed towards the centre of the curve
Cant allows trains to corner faster
The cant needed depends on speed – it must be set to accommodate the speeds of trains which will use the line
