On 14 November 2023, at 09:50 a.m. on the line marked M402 Sava rasputnica-Zagreb Klara, at the Zagreb Ranžirni station, at km 003+422, an accident occurred (Figure 1). When manoeuvring the brute of train No 81214 composed of 31 wagons of the Uagpps series from P-3 track to S-15 track via a hump, the first three wagons of the Ugpps series were derailed in the direction of pushing on switch No 213.
No one was killed or injured in this accident, and there was material damage to railway vehicles and railway infrastructure.
The causative factor of the accident in question is the derailment of the first three wagons of the Ugpps series (33 54 934 3108-4, 33 54 934 3112-5 and 33 54 934 3128-2) with both bogies in the direction of displacement, due to poor infrastructure i.e. track condition (Chapter 3.2.3, 4.2.1).
Contributing factors:
- small radius of switches in the Sub-hump (Chapter 3.1.8 and 3.2.3),
- the condition of the track structure was not able to withstand the prescribed axle pressure (Chapter 3.2.3, 4.2.1),
- clutch tension state within the manoeuvring composition (Chapter 3.2.3).
Systemic factors:
- no operating procedures are prescribed for manoeuvring when pushing trains in the Sub-hump zone in the ‘Instructions for work on the humps operation’ (Chapter 4.1.1).
The Agency for Investigation of Accidents in Air, Maritime and Railway Transport, based on the conducted investigation of this accident, in order to increase the safety of the railway system, issues the following safety recommendation to the Agency for Railway Safety:
✓ AIN/06-SR-01/2025
The Infrastructure Manager should revise the “Instructions for work on the humps operation” with regard to the operating procedures for manoeuvring when pushing trains in the Sub-hump zone.