# 7. Sightlines

## 7.1 General

7.1.1 Sightlines are measured from a point 1.05 m above the road surface to a point 1.2 m above top of lowest rail.

7.1.2 For the purposes of section 28(b) of the GCR, refer to the Class of Track in the Table below:

The table outlines the maximum allowable operating speed for freight trains and passenger trains for class 1 track through class 5 track.
Column 1

Class of Track
Column 2

The maximum allowable operating speed for freight trains is -
Column 3

The maximum allowable operating speed for passenger trains is -
Class 1 track 17 km/h (10 mph) 25 km/h (15 mph)
Class 2 track 41 km/h (25 mph) 49 km/h (30 mph)
Class 3 track 65 km/h (40 mph) 97 km/h (60 mph)
Class 4 track 97 km/h (60 mph) 129 km/h (80 mph)
Class 5 track 129 km/h (80 mph) 153 km/h (95 mph)

## 7.2 Determination of sightlines

In Figure 7-1,

1. SSD is the stopping sight distance and is calculated using the following formula:
SSD=0.278 x 2.5 x V + d
d = braking distance (m)
V = initial speed (km/h)
2. DSSD is the minimum distance along the line of railway that a crossing user must see approaching railway equipment from the stopping sight distance, and does not apply if the grade crossing is equipped with a Stop sign or warning system or sidewalks, path or trails.

DSSD is equal to the distance required for the design vehicle at its design speed to go from the stopping sight distance completely past the clearance point on the other side of the grade crossing.

DSSD = 0.278VT x TSSD (m)
DSSD = 1.47VT x TSSD (ft.)

Where,

VT = railway design speed in km/h or mph and
TSSD = [(SSD + cd + L)/0.278V] (s).

Where,

V = road crossing design speed (km/h)
cd = grade crossing clearance distance (m)
L = length of the grade crossing design vehicle (m)
3. DStopped is the minimum distance along the line of railway that a crossing user must be able to see approaching railway equipment from the stopped position at a grade crossing.

DStopped is equal to the greater of the distances that railway equipment at the railway design speed will travel during
1. the Departure Time for the grade crossing design vehicle calculated in accordance with article 10.3.2, or
2. the Departure Time for pedestrians, cyclists, and persons using assistive devices calculated in accordance with article 10.3.3.
Dstopped must be calculated by the following formula:
Dstopped = 0.278 VT x Tstopped (m)
Dstopped = 1.47 VT x Tstopped(ft.)

Where,

VT = railway design speed in km/h or mph
Tstopped = the Departure Times, calculated in accordance with article 10.3

Figure 7-1 – Minimum Sightlines – Grade Crossings

a) Sightlines for Users Stopped at a Grade Crossing (applicable to all quadrants).

b) Sightlines for Users Approaching a Grade Crossing (applicable to all quadrants)

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