Lecture 6 - Fundamental Design + Configuration Flashcards
Kinematic envelope
In addition to the static envelope, these reference lines also include the dynamic shift to a certain extend. If special vehicles exceed these requirements, the vehicle manufacturer must reduce the width of the vehicle
Structure gauge or Minimum clearance outline
Is the minimum space that must be kept clear by all adjacent construction objects along railway tracks in order to guarantee the safe journey of all vehicles. The difference between vehicle envelope and structure gauge results in the clearance between vehicle and fixed equipment.
There is a margin of safety between the vehicle gauge and the structure gauge
Vehicle and Structure Gauges (Required Clearance) acc. to BOStrab
No indication in relation to structure gauge
This is different for each public transport company
It is often not known and has to be calculated metrologically
The required clearance is determined relative to the vehicle
Static Vertical Road Stress
In the automotive sector the road wear is determined through the so-called influence number “v”. This grows with the 4th power of the wheel load.
An increase of the wheelset/axle load of 20% leads to an deterioration of the road of 107%
(1.2^4 - 1 = 1.07)
Permissible Axle Loads (track related acc. to EBO and track related acc. to BOStrab)
Main lines acc. to EBO 18t < Permissible axle load < 22.5t
Branch lines acc. to EBO 16t < Permissible axle load < 22.5t
Tramways and light rail acc. to BOStrab max 10 t
Metro railways acc. to BOStrab max 10 t
Wheelset load and load per meter
Wheelset load: Total weight of the vehicle divided in the number of wheelsets of the vehicle
Load per meter: Total weight of the vehicle divided in the longitude of the vehicle
Factors that influence the Axle Load
- Type of Running gear (single or double-axle)
- Boggie wheelbase/Distance between boggie centers
- Vehicle width
- Vehicle weight per meter
- Vehicle load capacity
Adhesive weight
Is the vehicle weight percentage that rests on the driving axles
Wa = WD / W * 100
Advanges and disadvantages of Four Axle car in a curve
\+ Longer cars \+ Heavier cars \+ Good curve negotiation \+ More stable straight run - Generally bigger center throw - Heavy running gear
Individual Car Basic Types
Single-Axle running gear (non-pivoting)
Double-Axle running gear (pivoting)
Vehicles with semi-trailer and common running gear (picture 6.2)
Identify
Vehicle and Structure Gauges (Required Clearance) acc. to BOStrab (picture 6.1)
Identify
Advanges and disadvantages of Individual Car Concept (Double Railcar)
+ Longer cars
+ Vehicles are individually manoeuvrable
+ Vehicles are freely configurable
+ Compensation of the vertical bending moment
- High ratio of running gear weight to the total weight
- Double joint coupling with relatively long junction
Advanges and disadvantages of Jacobs Concept (Articulated Railcar)
+ Lower ratio of running gear weight to the total weight
+ Single joint coupling with relatively short junction
- Shorter cars
- Vehicles remain in the trainset, separation only in the rail yard
- No compesantion of the bending moments
Advanges and disadvantages of Vehicles with Double Trailer (“Litter”)
+ Running gear occupy little space under the car body
+ Litters freely configurable in the internal space
- Large forces in the joints
- Large twisting torque between the running gear and the car body when negotiating curves
