BS 16186-5:2021 pdf download – Railway applications — Driver’s cabs Part 5: External visibility for tram vehicles
5 Forward visibility
For the seated driving position, the forward visibility requirements of 5.2.1 shall be ensured (see also Annex A and Annex B, Figure B.1).
The horizontal distance from the driver’s eye to the windscreen in seated position shall be a minimum of 500 mm and an absolute maximum of 1 715 mm.
The sightlines as defined in 5.2 shall not be infringed by any permanent equipment of the rolling stock (except for the wiper), whether inside or outside the cab.
All visibility criteria shall be applied using both dummies defined in 4.2.
The visibility criteria do not apply to driver instructor locations.
5.2 Forward visibility requirements
A good outside field of vision enables the driver to anticipate hazardous situations, taking into account the exterior environment when the tram vehicle is moving. The cab design shall enable all drivers:
— to see the track (free from obstacles, track elements in the correct position);
— to see and recognize the signals intended for them in an adequate sighting distance;
— to anticipate and detect hazard by having a large field of vision taking account of the technical constraints and the physiological data (use of the binocular field of vision);
— to detect a hazard by limiting the hidden areas: e.g. detection of a pedestrian of 6 years of age or over when the tram vehicle starts moving in area used by pedestrians (in particular stations).
These objectives are met if the requirements listed below are fulfilled.
The visibility for the driver from the normal seated position respecting the comfort articular angles, as defined in EN 16186-8 4 , with the hand on the master controller, is covered by the following assessment.
The assessment is based on standard reference points of the two driver dummies, on a vehicle in design mass under normal design payload conditions according to EN 15663 on a straight and level track.
Visibility to the outside shall be possible within a minimum angle of 165 °, symmetrical to the sagittal plane (see Figure 5). The forward viewing field is verified on a horizontal level at eye level.
Assessment for visibility shall at least be done with one eye point. It can be done with two eyes if needed to fulfil the criteria.
NOTE It is not necessary to do the assessment for the complete range of the different comfort angles.
5.2.3 Visibility of external signals The reference points shall be:
— high reference point: positioned at a height of 6,30 m above the top of rail at a distance of 10 m from the front plane of the buffer or automatic coupler or the most external leading point of the vehicle and positioned laterally right and left from the straight track axis at a distance of 3,50 m;
— low reference point: positioned at top of rail level at a distance of 15 m from the front plane of the buffer or automatic coupler or the most external leading point of the vehicle and positioned laterally right and left from the straight track axis at a distance of 3,15 m.
The demonstration of forward visibility shall be done based on a drawing with theoretical lines of sight for both driver dummies.
It is recommended that the longitudinal distance at which low reference points are visible should be reduced. With this assessment all effects like track curvature, track geometry and vehicle conditions are completely covered, i.e. no additional requirements resulting from those effects shall apply.
The windscreen shall enable upwards visibility of 25 ° in relation to the horizontal level at eye height in the sagittal plane for the two dummies (see Figure 3).
5.2.4 Close outside visibility In case of close-up obstacles, the driver shall have a direct line of sight to the complete area in front of the vehicle. This requirement is assumed to be fulfilled when a cylinder of 1 100 mm in height and 300 mm in diameter, with its centre placed on the top of rail 650 mm away from the foremost surface of the tram is always be detected by the driver. The detection shall be possible within the forward field of view (as defined in 5.2.2).BS 16186-5 pdf download.