Page 336 - 360.revista de Alta Velocidad - Nº 5

Sepúlveda Abad, Silvia. Lastra de la Rubia, Emilia.

1. Introduction

When a high speed train enters in a tunnel there is an overpressure and depression in head and
tail that propagates along it at the speed of sound, reflecting each time they reach the portals
of tunnel. These variations, among other aspects like the increasing aerodynamic drag of train
can affect the health and comfort of passengers.
To avoid the above effects designers, have to comply with several criteria. By one hand, the
Health Criterion included in Infrastructure Technical Specification of Interoperability (TSI) that is
mandatory. On the other hand, Comfort Criteria included in the different recommendations and
national standards which at the end result more restrictive in terms of sizing of the final crosssection.
Throughout this paper, in a perspective vision about what these 25 years have been occurring
will be transmitted in order to put in the reader’s mind the fast evolution and improvements
that the Aerodynamics Studies have introduced in the designing of high speed tunnels.

2. Current spanish regulation

In Spain two main standards are actually employed in relation to sizing the free cross-section
due to aerodynamic constraints of high speed tunnels.

2.1 Health Criterion

Infrastructure Technical Specification of Interoperability (TSI), 2014, November 18th, regulates
the health criteria. In the article 4.2.10.1 Maximum pressure variations in tunnels, states the
following:

• Any tunnel or underground structure intended to be operated at speeds greater than or
equal to 200 km/h has to provide that maximum pressure variation, caused by the passage
of a train running at the maximum allowed speed in the tunnel, do not exceed 10 kPa during
the time taken for the train to pass through the tunnel.
• Above requirement has to be fulfilled along the outside of any train complying with the
Locomotives and Passenger TSI.
This is mandatory for all cases, and trains are considered non-sealed trains.
2.2 Comfort Criteria

For the regulation of comfort criteria, in Spain there are 2 main standards.

Draft of the IFI (“Instrucción Ferroviaria para el proyecto y construcción del subsistema de
Infraestructura”), now in approval stage, states the following criteria:

Pressure Difference
TRAIN TUNNEL t(s)
(kPa)
Single track 2 4
Non sealed trains
Double track 4 4

Single and Double 1 1
Sealed trains (τ = 6s)
tracks 2 10

Table 1 Comfort criteria included in draft of IFI

334 360.revista de alta velocidad