Railway and Light Rail Transit: Design and Operation

Posted on Dec 16, 2024 in Technology

1. Positive and Negative Effects of Rail Transport

Positive Effects:

  • Environmentally friendly connection between places of interest
  • Support for global trading and effective manufacturing
  • Job creation (drivers, operators, assistants)

Negative Effects:

  • Air pollution
  • Contamination of water and soil
  • Biodiversity loss and landscape fragmentation
  • Accidents involving rail vehicles
  • Waste generated by railway traffic
  • Noise and vibration caused by railway transport

2. Track Body Functions and Sub-ballast Materials

Two most important functions of the track body:

  • Good bearing capacity to withstand great loads
  • Well-drainage properties

Materials usually used in sub-ballast layers:

  • Crushed stone mixture 0/32
  • Mineral mix
  • Recycled concrete

3. Fastenings: Functions and Types

Main functions of fastenings:

  • Maintain a constant track gauge and transverse rail inclination
  • Transfer loads from rails to sleepers
  • Moderate vibrations caused by train traffic

Types of fastenings:

  • Direct or indirect
  • Rigid or elastic
  • Screw-type / spring-type or clip-type

4. Tramway Track Parameters in the Czech Republic

  • Minimum curve radius: 50 m (passenger traffic), 25 m (normal conditions), 20 m (turning loops)
  • Maximum gradient: 7.0% (9.0% in existing tracks)
  • Minimum distance between tracks: 3000 mm

5. Tramway Track Superstructure Requirements

  • Ensure automatic steering
  • Low rolling resistance
  • Return path for electric current
  • Transmission of the load to the substructure

6. Y-Steel Sleepers: Advantages and Disadvantages

Advantages:

  • Low weight
  • Low height
  • Ballast saving
  • High resistance to displacement
  • Easy to recycle
  • Fewer sleepers needed (803 instead of 1667 per km)

Disadvantages:

  • High cost
  • Difficult installation

7. Standard Track Gauge

Standard track gauge: 1435 mm

Measurement point: 14 mm below the top of the rail (9 mm in grooved rails)

8. Rail Vehicle Noise Sources

  • Rolling noise: Wheel-rail interaction, coach body-carriage connection, brakes
  • Driving noise: Diesel engine, traction motors and fans, compressors, suction fan, coach body oscillation
  • Aerodynamic noise: Airflow over the train at high speeds
  • Pantograph noise

9. TEN-T: Trans-European Transport Network

The Trans-European Transport Network (TEN-T) is a planned set of road, rail, air, and water transport networks in Europe. It emphasizes providing integrated and intermodal long-distance, high-speed routes.

10. Pan-European Corridors

Another network project besides TEN-T, involving Central and Eastern European countries. It resulted in four main railway corridors in the Czech Republic (almost 2000 km).

11. Standard Gauge Definition

Standard gauge: 1435 mm

It is the spacing between the rails on a railway track, measured 14 mm below the top of the rail head between the inner faces of the rail heads.

12. Common Gauges in Czech Railways

Most common: Standard gauge (1435 mm)

Other gauges: 760 mm (narrow gauge), 1000 mm (meter gauge)

13. Railway Substructure Components

  • Track body: Sub-ballast layers, base, formation layer
  • Substructure structures: Walls, bridges
  • Transport sites and roads
  • Other structures and equipment

14. Railway Superstructure Components

  • Rails
  • Sleepers
  • Ballast
  • Fastenings and track fittings

15. Types of Walls in Railways

  • Retaining walls: Above sub-ballast layer, retain slopes
  • Embankment walls: Beneath sub-ballast layer, contain embankments
  • Revetment walls: No static function, protect slopes and prevent rockfalls
  • Culvert walls: Lead water across a railway track
  • Noise barriers: Protect from noise in urban zones (passive noise measure)

16. Revetment Walls: Purpose

Revetment walls have no static function. They protect rock slopes from weathering and keep falling rock parts away from the track.

17. Waste in Rail Traffic

Two main groups of waste:

  • Old railway vehicle wrecks (repair, reuse, or ecological disposal)
  • Material from railway superstructure disposed of during reconstructions

18. RID: Regulation for International Transport

RID (Regulation for International Transport of Dangerous Goods) is the basic regulation for the international transport of dangerous substances, including banned substances and transport requirements.

19. Rail Connection Devices

  • Screw joint with a fishplate
  • Dilating devices
  • Continuously welded rail

20. Concrete vs. Timber Sleepers

Timber sleepers:

  • Suitable for unusual adjustments
  • Shorter lifetime without impregnation
  • More elastic
  • Easier to cut and adjust

Concrete sleepers:

  • Most common
  • Low maintenance
  • Great longitudinal and transversal resistance
  • More rigid, requiring more ballast for elasticity

21. Required Properties for Ballast

  • Distribute stresses
  • Absorb vibrations
  • Ensure resistance
  • Enable rainwater drainage
  • Allow maintenance of track geometry
  • Made of hard stone with an angular shape
  • Frost resistant
  • Elastic

22. Railway Switches: Definition and Types

Switches and crossings change direction, cross another track, or split/join tracks.

  • Turnout: Allows a track to be split in two
  • Crossing: Two tracks meet at grade without a change of course

23. Slab Track vs. Ballast Track

Slab track:

  • Lower maintenance costs (higher lifetime)
  • Higher construction costs
  • Lower thickness (advantageous in tunnels)
  • More stability
  • Noisier
  • Some repairs are more difficult

24. Cog Railway

Used for steep railways where adhesive forces are insufficient. Cogs (teeth) aid adherence and utilize locomotive power in extreme situations.

25. Cant

Cant is the track superelevation of the external rail in curves. 20 mm < p < 150 mm

26. Sound and Noise Definition

Sound: Any pressure variation detectable by the human ear.

Noise: Any annoying or disturbing sound; unwanted auditory information.

27. Vibration

Vibration is sound traveling through any form of matter. It is a transversal wave motion, while sound is a longitudinal wave motion.

28. Sound Thresholds

  • Normal speech: Around 55 dB
  • Discomfort threshold: Around 110 dB
  • Pain threshold: Around 130 dB

29. Rail Vehicle Noise Sources by Origin

  • Rolling noise
  • Driving noise (engine, fans, etc.)
  • Aerodynamic noise
  • Pantograph noise

30. Light Rail Transit (LRT) vs. Rail Rapid Transit (RRT)

LRT:

  • Mainly uses ROW category B
  • Electrically powered units: 1-4 cars

RRT:

  • Uses ROW category A
  • Superior in speed, capacity, safety, and efficiency
  • Often operates underground
  • Electrically powered units: 4-10 cars

31. ROW: Right Of Way Categories

ROW determines the priority of crossings with other vehicles.

  • ROW category A: No crossings or legal access by other vehicles (or fully protected crossings)
  • ROW category B: Longitudinally physically separated from other vehicles, but with grade crossings
  • ROW category C: Circulating on streets with mixed traffic

32. Measures to Improve LRT on ROW Category C

  • Elimination of left turns
  • Prohibition of cross traffic
  • Actuation of signals at intersections
  • Reserved transit lanes

33. LRT Track Parameters in the Czech Republic

  • Minimum curve radius: 20-25 m
  • Maximum gradient: 15% (10% recommended)

34. Light Rail Rapid Transit vs. Regular LRT

  • Fully separated ROW
  • Operating speeds: 40-60 km/h
  • Automated operation
  • Third-rail power supply

35. RRT Track Parameters in the Czech Republic

  • Minimum curve radius: 100-200 m
  • Maximum gradient: 5-7%

36. Monorail Characteristics

  • Track formed by one rail
  • Usually elevated track
  • Vehicles can be suspended or move on a narrow guideway
  • Vehicles are wider than the guideway

37. Level of Service (LOS)

An overall measure of all service characteristics affecting users.

38. Contemporary Tramway Characteristics

  • Manual/visual vehicle control
  • Exclusive ROW: 0-40%
  • Operating speed: 12-20 km/h
  • Maximum speed: 60-70 km/h
  • Stop spacing: 250-500 m
  • Low platforms
  • Overhead power supply

39. Track Superstructure Components

  • Rails
  • Fastenings
  • Sleepers in ballast, precast concrete panels, or in-situ concrete slabs

40. Track Superstructure Requirements

  • Automatic steering
  • Low rolling resistance
  • Return path for electric current
  • Transmission of the load to the substructure

41. Rail Support Components and Materials

  • Sleepers: Concrete, timber, steel, plastic
  • Precast concrete panels
  • In-situ concrete slabs