Accident
investigators


have
confirmed
that
the
fatal
head-on
collision
on
the
Cambrian
line
in
mid-Wales
on
21
October
was
caused
by
wheel
slip,
and
that
although
the
driver
of
the
affected
train
made
an
emergency
brake
application
the
automatic
sanders
which
should
have
been
triggered
by
the
slipping
wheels
were
blocked.

The
train
concerned,
1J25
from
Shrewsbury
to
Aberystwyth,
continued
through
the
passing
loop
at
Talerddig
in
Powys
and
collided
on
a
descending
gradient
with
train
1S71
from
Machynlleth
to
Shrewsbury.

One
passenger
died
and
four
others
were
seriously
injured.
Eleven
more
also
needed
hospital
treatment
for
their
injuries.

The
Rail
Accident
Investigation
Branch
says
although
neither
train
was
derailed,
‘significant
damage’
was
caused
to
the
leading
vehicles.

The
trains
were
formed
of
two-car
Class
158
units,
operated
and
maintained
by
Transport
for
Wales. They
were
removed
on
25
October,
and
the
line
reopened
on
28
October.

The
RAIB
said:
‘Initial
analysis
of
data
from
the
on-train
data
recorder
fitted
to
train
1J25
shows
that
the
driver
applied
service
braking
to
slow
the
train
as
it
neared
the
loop
at
Talerddig.

‘Around
40
seconds
after
the
first
service
brake
application,
the
OTDR
records
an
emergency
brake
demand
being
made.
This
emergency
brake
demand
remained
in
place
until
the
collision.
OTDR
data
shows
that
wheel
slide
started
during
service
braking
and
was
constant
during
emergency
braking.

‘Train
1J25
then
entered
the
loop
at
Talerddig.
Although
the
train
slowed
while
passing
through
the
loop,
it
did
not
stop
before
passing
the
block
marker
near
the
exit.

‘There
is
conflicting
evidence
relating
to
the
speed
of
the
trains
at
the
point
of
collision.
Initial
analysis
indicates
that
train
1J25
was
travelling
at
between
24
km/h
(15
mph)
and
39
km/h
(24
mph),
while
train
1S71
was
travelling
at
around
10
km/h
(6
mph)
in
the
opposite
direction.’

The
RAIB’s
inquiry
is
continuing.

If
defective
sanders
were
a
cause
of
the
collision,
it
will
not
be
the
first
time
that
a
driver
has
lost
control
for
this
reason.

A
Southeastern
train
ran
through
Stonegate
station
on
8
November
2010
and
continued
out
of
control
for
more
than
four
kilometres
before
stopping.
There
was
no
collision
and
no
one
was
injured,
but
the
RAIB
identified
‘poor
adhesion
conditions’,
and
said
the
leading
sand
hoppers
were
‘almost
certainly
empty’.