2 - Priorities and Drivers for Rail in Multi-Modal Transport

Question 1

Change in 1830

Answer 1

Canals were main form of transport
First intercity railway opened in 1830 between Liverpool and Manchester

Question 2

Outcomes of the Rail Technical Strategy

Answer 2

Mode of choice for passenger and freight
Railway that attracts investment and talent
Accessible and affordable mode that supports UK economy
Sustainable operations with positive environmental impact

Question 3

Four C’s challenges

Answer 3

Carbon - climate change, energy supply
Capacity - how to get more people/things through the network
Cost - how to keep cost under control, reduce support from government
Customers - give people better experience of the railway

Question 4

Points about carbon challenges

Answer 4

Origin of goal is in global warming, but also energy costs and possible tax on CO2 emissions
Rail emissions are only 0.5% total UK CO2 emissions
Moving to electric rather than diesel trains may help, but then need to consider source and availability of electricity

Question 5

Aim of carbon challenge

Answer 5

Halve CO2 output by 2038
Value to industry of £0.5 billion/year

Question 6

Aim of capacity challenge

Answer 6

Double capacity by 2038
Value to £7.5 billion/year (2009 prices)

Question 7

How to reduce train crowding when train length and frequency are limited?

Answer 7

Better design of train interiors
Technology to reduce headway between trains

Question 8

How to increase freight traffic without reducing passenger capacity?

Answer 8

Slow-moving freight takes up too much network capacity
Could be sped up?
Passenger and freight services could be better integrated through new vehicle designs?

Question 9

Examples of targeted aims to achieve 4 C’s

Answer 9

Running trains closer together
Efficient passenger flows through trains and stations
Optimum energy use

Question 10

Reasons why transport demand is changing

Answer 10

New business models: transport related (e.g. Uber); work accommodation changes (working from home)
Digital networks (5G): enables working from home
Ageing population: both travellers and workforce

Question 11

Points about inspecting overhead lines

Answer 11

Overhead lines are contacted by train pantograph to pick up electric power
Overhead wires can suffer wear, failed joins, corrosion and fatigue

Question 12

Modelling overhead lines

Answer 12

Sheffield working with Furrer+Frey and Network Rail to model life of overhead line
Aim - predict forces produced by pantograph loading combined with wire tension
Produced FEA model of contact wire dynamics and damage models of how wire stress drives failure modes
Benefits: predictable renewal rather than responding to wire failures; better specification of new equipment

Question 13

Rolling contact fatigue problem points

Answer 13

High contact stresses at wheel-rail interface cause metal fatigue and so cracks and rail breaks
Measurement of surface crack length used to assess damage (ultrasound and eddy current inspection)
If early damage stages found, rail can be ground down, removing cracks and extending rail life
Otherwise severe grinding or rail replacement needed

Question 14

Lab-based rolling contact testing points

Answer 14

Rail and wheel discs run together (using real materials)
Loaded to simulate train weight (smaller loads must be applied to achieve same contact pressure on smaller specimens as on full-size components)

Question 15

Why are rail and wheel discs separately driven?

Answer 15

With only one disc driven, the discs would just be rolling together
Braking/traction creates combination of rolling and sliding

Question 16

Planning for reduced energy use problem and solution

Answer 16

Problem - start-stop operation and conflict between trains at junctions reduces capacity and increases energy use
Solution: modelling and planning train movements; in-cab Driver Advisory Systems to help regulate speed and position

Question 17

Effects of railhead leaf contamination

Answer 17

Increased safety risk in braking (increased stopping distance)
Safety risk from failure of track circuits to detect trains
Reduced performance through wheel slip or spin, causing an increase in delay minutes and wheel damage

Question 18

Physical solution to leaves on the line

Answer 18

Water-jetting
Over 100MPa water jet directly onto railhead
Cleans rail of debris
Effective at speeds up to 40mph

Question 19

Chemical solution to leaves on the line

Answer 19

Removing leaf layer by disrupting chemistry of bond to the rail
‘Cirtaclean’ changes pH of railhead to disrupt existing leaf film and to help prevent reformation

Question 20

Rail damage from poor traction control systems points

Answer 20

Can cause wheel spin or slides
High loads on contact means that any sliding delivers lots of heat and energy into rail and wheel
Quick changes to metal microstructure, can lead to cracks and/or accelerated wear

Question 21

Range of friction coefficients at wheel-rail contact

Answer 21

0.1-0.5