General Principles for the Design of the Cross-section - Tunnel Engineering: Basics and Additional Services for Design and Construction - page 9

space outside the outline of the clearance gauge. The passage width of the escape and res-
cue path should be at least 1.20 m, and the clear headroom at least 2.20 m.
The illustration (Fig. 1-5) shows an example of these requirements and the other details of
the clearance gauge for a two-track tunnel with three-centred arch section on a high-speed
line. The corresponding guideline details for a single-track tunnel with circular or three-
centred shape of the cross-section can be found in Ril 853.
2. Tunnels for express traffic at 160 km/h < v E ≤ 230 km/h
The cross-section of a rail tunnel for express traffic only differs from that for high-speed
travel in the specified dimensions according to the guideline detail. The requirements for
safety spaces and escape routes are formulated independently of design speed, so the require-
ments are identical for all design speeds. Ril 853 specifies a track spacing of only 4.00 m
for express traffic in two-track tunnels, so the required formation width at u = 0 reduces to
11.60 m. The required spacing of track centreline to edge of formation remains at 3.80 m.
The radius of a circular cross-section also reduces to r = 6.10 m, from which an altogether
smaller cross-sectional area of A = 79.2 m 2 above TOR can be calculated. As with tunnels for
high-speed traffic, individual parameters can also vary with the selection of as ballastless or
conventional permanent way. This is illustrated below with a guideline detail for a two-track
tunnel for express traffic with circular cross-section according to Ril 853 (Fig. 1-6).
Figure 1-6 Guideline detail for a two-track express tunnel with circular section according to Ril 853.
3. Passenger and goods traffic at v E ≤ 160 km/h
For passenger and goods traffic with a design speed of v E < 160 km/h, the Ril 853 does not
provide any guideline details for two-track cross-sections. Because the traffic is mixed,
only single-track tunnels should be used in this case according to the guideline for civil