Lecture 7 - Wheel-rail interaction

Question 1

Coordinate System for Rail Vehicles

Answer 1

X: Vehicle longitudinal direction = driving direction
Y: Vehicle lateral direction
Z: Vehicle vertical direction

Question 2

Vehicle Elements

Answer 2

Main part: vehicle structure + underframe = carbody
Running gear: Secondary suspension, bogie frame, primary suspension, bearing, wheelset
Vehicle interior equipment

Question 3

Draw and identify vehicle and track elements (Figure 7.1 )

Answer 3

Identify

Question 4

Track Elements

Answer 4

Superestructure: rail, rail fastening, sleeper, ballast
Foundation: blanket, formation level, subsurface

Question 5

Track layout

Answer 5

Is the spatial location of the track axis (track center line) on the ground
Note: top view of a layout looks like an L with a curve
Elevation profile of a layout has the Z and the X

Question 6

Types of Open Superstructures

Answer 6

Sleeper pads for ballasted superestructure: concrete sleepers, wooden sleepers and plastic sleepers
Elastic support for the ballastless superestructure: Solid ballastless track, special constructions

Question 7

Purpose of the Open Superstructure Elements

Answer 7

Sleepers: keep rails spaced to the correct gauge, distribution of the loads over large surfaces, vibration protection, ballast protection
Ballast: can compensate subsurface settlement, drainage of water, regular filling and cleaning necessary (expensive), edge wear, hence replacement necessary (expensive)
Solid ballastless tack: requires low-settling of the subsurface, drainage necessary, higher adquisition costs, lower maintenance costs, additional structure noise reduction necessary

Question 8

Types of Sleepers and explain them

Answer 8

Wooden sleepers: expensive, structure-borne noise insulating, toxic, rot risk
Plastic sleepers: cheaper, structure-borne noise insulating, longer lasting, mostly at rail switches
Concrete sleepers: cheaper, structure-borne noise conducting

Question 9

Draw and identify wheelset elements (Figure 7.2)

Answer 9

Identify

Question 10

Draw and identify Identify Wheel Profile for Main Line and Metro Railways (Figure 7.3)

Answer 10

Identify

Question 11

Main dimensions of Wheel Profiles for Main line

Answer 11

Flange thickness = Flange width: d = e > 32 mm
Flange height h = 28 mm
Wheel width: 135 mm
Flange angle ymax : 70º

Question 12

Draw and identify Wheel Profile for trams (picture 7.4)

Answer 12

identify

Question 13

Main dimensions of Wheel Profiles for Tramway

Answer 13

Flange thickness = Flange width: d >= e > 20.5 mm
Flange height h >= 20 mm
Wheel width: 87.5 - 125 mm
Flange angle ymax : 66-76º

Question 14

Wheelset geometry according to EBO

Answer 14

min             max
Wheelset gauge: 1410 mm - 1426 mm
back to back dimension: 1357 - 1363 mm
Wheel width: 133 - 140 mm
flange width: 22 - 33 mm
flange depth: 26 - 36 mm

Question 15

Draw and identify elements of the Wheelset geometry (Figure 7.4)

Answer 15

Identify

Question 16

Draw and identify elements of the Rail Profile (Figure 7.5)

Answer 16

Identify

Question 17

Draw and identify elements of the Grooved Rail Profile (Figure 7.6)

Answer 17

Identify

Question 18

Wheelset on Track: Main Line nominal values and tolerance range

Answer 18

Nominal value / Tolerance range
Wheelset gauge s: 1425 mm / 1410 - 1426 mm
Track gauge S: 1435 mm / 1430 - 1470 mm
Gauge play S - s: 10 mm / 4 - 60 mm

Question 19

Draw and identify elements of the track geometry with deep/shallow-groove rails (Figure 7.7)

Answer 19

Identify

Question 20

Which are the possible Wheel-rail contact situations? Draw them (Figure 7.8)

Answer 20

1 point tread contact
1 point flange contact
2 points flange contact
2 points wheel back contact
1 point shallow groove contact