At 0743 on 25 April 2001, the Countrylink XPT daylight service
ST3 (train 8622) left Sydney bound for Melbourne. The train
consisted of a lead power car followed by seven passenger cars
designated from 'A' through to 'G' and a trailing power car. On
board the train was a crew of five- the driver, a passenger service
supervisor and three passenger attendants- and 127 passengers.
The run from Sydney south was routine. No problems were reported
at the driver changeover in Junee at approximately 1354. At 1528
the train arrived in Albury where the passenger service supervisor
and three passenger service attendants changed over. The train
departed from Albury Station at 1532, approximately 30 minutes
late, with 98 passengers on board.
After leaving Albury Station, the driver accelerated to 80 km/h
and maintained that speed until approaching the Melbourne end of
the Wodonga coal sidings, where he reduced the train speed to
slightly below the 40 km/h posted speed. Shortly after this, the
train passed the Hovell Street level crossing in Wodonga and
continued to round the tight right-hand curve in the main line
before the High Street level crossing. The train's speed was
approximately 25 km/h. As the train entered this section of curve,
the driver applied some power to maintain the train's speed through
the curve.
At approximately 1538 at 301.1086 km, the inner wheel on the
lead axle of the lead bogie (NHA 198B) of car 'E' (XF 2214) dropped
from the low rail of the curve. At 301.105 km the inner wheel
dropped completely from the low rail into the track fourfoot. The
train travelled approximately 2.75 m further until the outer wheel
on the same axle climbed over the high rail and onto the ballast
shoulder on the outside of the curve. At 301.0911 km the trailing
wheel-set of the bogie also derailed with the outer wheel climbing
over the high rail and the inner wheel simultaneously dropping into
the four-foot. The bogie, now completely derailed, travelled in
this condition for approximately 950 m until the train was brought
to a stop by the driver. The driver had stopped the train in
response to a passenger emergency alarm which had been initiated by
the passengers in car E.
The derailment occurred on the sharpest curve on the main line
between Sydney and Melbourne. The alignment at this point in the
main line was originally dictated by the presence of a crossing
diamond where the broad gauge branch line to Bandiana had crossed
the standard gauge main line. The alignment of the curve had not
been changed since the closure of the branch line and the removal
of the diamond in 1997.
Assessment of the track at the derailment site revealed a number
of factors which contributed to the derailment, the most
significant of which was the condition of the high rail fasteners
which resulted in gauge widening of up to 49 mm at the point of
derailment.
The derailment was unusual in some ways as there had been other
freight and passenger train traffic on the line earlier in the day
without incident. In addition, the derailment involved only one
bogie in the middle of the train with bogies in the same train
passing safely over the site before and after bogie NHA 198B had
derailed. This indicates, that while the track-based elements were
the primary causal factors, it was the combination of the
vehicle-based and track-based factors that caused the
derailment.
Inspection of the bogie which derailed revealed some factors
which contributed to the derailment including a thin flange on the
number-1 wheel and the poor condition of the bogie's side bearer
yaw friction pads.