STRUCTURE GAUGE AND CLEARANCES .1 Definitions

2.5.1.1 The normal co-ordinated axes of a vehicle are defined as those orthogonal axes, normal to the longitudinal centre line of the vehicle, where one axis called the wheel line is the line connecting the points of bearing of pairs of wheels on the rails and the second, perpendicular to the first, called the vehicle centre line, is central between the wheels.

2.5.1.2 The normal co-ordinated axes of the track are defined as those orthogonal axes, normal to the longitudinal centre line of the track, where one axis, called the rail line is the common tangent to the tops of the rails and the second perpendicular to the first, called the track centre line, is central between the rails.

2.5.1.3 The static load gauge is defined as the profile related to the theoretical normal co-ordinated axes of the passenger vehicle outside which no part of the vehicle shall protrude when the vehicle is stationary and unloaded and when all play in the axles and suspension are uniformly distributed either side. Building tolerances for the vehicle are included in the static load gauge.

2.5.1.4 Horizontal throw is the distance measured parallel to the rail line of the vehicle centre line from the track centre line when a vehicle is on a horizontal curved track, and all play in the axles and suspension are uniformly distributed either side.

Horizontal throw reaches (arithmetic) maximum midway between bogies and at the ends of the vehicle. These throws are called centre throw and end throw respectively.

2.5.1.5 Vertical throw is defined in a similar manner when a vehicle is on vertically curved track.

2.5.1.6 The Kinematic Load Gauge is defined as the vehicle profile related to the designed normal co-ordinated axes of the vehicle which covers the maximum possible distances from the vehicle centre line to any part of the vehicle taking into account the most unfavourable positions for running, including tolerances and wear

2.5.1.7 The Kinematic Envelope is defined as the profile related to the designed normal co-ordinated axes of the track which covers the maximum possible distances from the track of any part of the vehicle taking into account the most unfavourable positions for running, including tolerances and wear of the track. When enlarged horizontally and vertically on curved track to allow for throw, it is referred to as the

2.5.1.8 The Structure Gauge is defined as the profile related to the designed normal co-ordinated axes of the track into which no part of any structure or fixed equipment may penetrate, taking into account all deformations and movements.

2.5.1.9 The Service Vehicle Load Gauge is the Kinematic Load Gauge for those rail vehicles used for construction and maintenance

2.5.1.10 The Construction Gauge is the structure gauge, which shall apply during construction until the time that trial running commences.

2.5.2 Train and Track Vehicles

2.5.2.1 All rail vehicles used for construction and maintenance will conform to the service vehicle load and shall not influence the design of the civil works.

2.5.3 Structure Gauge

2.5.3.1 The Structure Gauge shall be based upon the Kinematic Envelope in such a way that each point on the perimeter of the Kinematic Envelope is enlarged vertically upwards by 50mm and horizontally by 100mm (two points to be constructed for each point on the Kinematic Envelope). The Structure Gauge is the largest envelope based on the points constructed as described above. Below the vehicle, the Kinematic Envelope is enlarged by 15mm to form the lower limit of the Structure Gauge. The shortest distance between the Kinematic Envelope and the Structure Gauge at any point is the Clearance at that point.

2.5.3.2 Special provisions will be made to permit the intrusion of the platform nosing, the platform screen doors and platform edge columns into the Structure Gauge.

2.5.3.3 The Structure Gauge for curved track shall in all cases include an allowance for the maximum vehicle throw, both horizontal and vertical at the location being considered in accordance with Clause 2.5.4.1.

2.5.4 Throw

2.5.4.1 Horizontal throw can take the form of either centre throw or end throw.

They are inversely proportional to the curve radius. When a vehicle is fully on a circular curve throw may be calculated from the formulae.

Centre throw (mm) = B² 10³

8R

End throw (mm) = (T²-B² )10³

8R

B= Distance between bogie centres (metres) R= Radius in metres

T= Overall length of vehicle (metres)

2.5.4.2 On circular curves, throw may be calculated in accordance with Clause 2.5.4.1 above. On transitions and on straight track adjacent to transitions, throw shall be calculated based on the vehicle characteristics. A “swept envelope” method may be employed.

2.5.4.3 An allowance shall be made for horizontal throw throughout the length of points and crossing and on the straight track adjacent to these areas. Similarly a “swept envelope” method may be employed.

2.5.5 Clearance to Structure Gauge

2.5.5.1 All structure and equipment shall be designed to be clear of the Structure Gauge with adequate allowance made to take into account all tolerances of construction and fixing, and for all deflections and displacements.

2.5.5.2 All moveable equipment, hinged doors, windows, etc close to the track shall be positioned so that they are not within the Structure Gauge at every position of movement. All covers to sumps, pits, etc within the track slab shall not infringe the Structure Gauge when in the open position.

2.5.5.3 Where two tracks are side-by-side with each track capable, within the constraints of the signalling system, of passing trains at the same time, the minimum clearance between the two tracks shall be such that the Structure Gauges do not overlap.

2.5.6 Clearances at Platform Edge

2.5.6.1 Alongside the station platform limited intrusion into the Structure Gauge of the platform edge, platform edge columns and screen doors is permitted; see Structure Gauge Drawing.

2.5.6.2 The platform edge shall be set such that 75mm clearance is provided horizontally between the static load gauge and the platform edge.

Where a curved and/or canted track is less than 20 m from the platform, the platform edge distance shall be increased to account for effect of cant and throw. The distance shall be calculated precisely, for the worst position of the train.

2.5.6.3 The screen doors shall be set at a distance of 115mm (+10 - 0 mm) from the static load gauge.

2.5.6.4 Intrusions into the Structure Gauge permitted in Clause 2.5.6.1 shall

2.5.6.5 Passageway and staircases beyond the platform and end barriers near ends of platform shall be designed to be clear of Structure Gauge.

2.5.6.6 Alongside depot platforms, intrusions into the Structure Gauge are also permitted. The platform edge shall be set at 115mm (+20 - 0 mm) from the static load gauge where the curved track is at least 20 m beyond the platform.

CHAPTER 3 LOADS

3.1 GENERAL

Loads shall be determined from The Building Control Regulations 4th Schedule, BD 37/88 (see Design Criteria clause 1.2.2) and BS 6399 except where stated otherwise in this Chapter. In any circumstances where there is a discrepancy between the relevant standards and regulations the more onerous shall apply.

The following loads and effects shall be considered in the design of all structures:

(a) Dead Load

(b) Superimposed dead load

(c) Load from adjacent building foundations or other structures (d) Surcharge load

(e) Live load (primary and secondary) or imposed load (f) Earth Pressure

(g) Hydrostatic Pressure (h) Temperature effects

(i) Effects of shrinkage and creep in concrete (j) Erection forces and effects

(k) Differential settlement (l) Wind Load

(m) Collision Load

(n) Any other forces and effects arising out of the special nature of any structure

This Chapter specifies the general loading requirements. For loading requirements specific to the type of structure being designed reference shall be made to the relevant Chapter.

The loads given in these Design Criteria shall be treated as unfactored (nominal or characteristic) loads for design purposes unless specifically noted otherwise (Therefore partial safety factors shall be applied in accordance with the limit state methods of the relevant standard, for example BS 5400, SS CP 65, etc.).

All unfactored (nominal or characteristic) live loads, imposed loads and superimposed dead loads shall be shown clearly on a comprehensive set of loading plans.

3.2 LOADS FROM RAILWAY VEHICLES