Railcar shunt causes Propylene release
There were six stationary railcars in a loading bay. One of the railcars
was empty whilst the remaining five all contained propylene. One of the full
tankers had been overfilled, and was connected by hoses to the loading bay
fixed pipework so that it could be partially emptied. The car valves were
open but the fixed loading bay valves were closed. A further five full
railcars were on this line. The end car was obstructing the track points for
access to other loading bays. Either through lack of communication or
misunderstanding, the locomotive crew believed that the propylene train was
ready to be moved, and decided to shunt the five full cars further down the
line to clear the track points. The train was moved approximately five feet,
which was sufficient to break both the liquid and vapour stubs on the
connected railcar. About 10 tonnes of propylene were released over a period
of eight minutes.
The emergency services were called and attempts were made to close the
foot valve hydraulically. This failed and an operator had to enter the
vapour cloud and close the block valves on the railcar manually.
Fortunately, the cloud did not ignite, but the operator sustained cold
Failures in technical measures
Tony Fishwick, ‘Railcar Shunt Causes Propylene Release’, Loss
Prevention Bulletin, Issue No. 146, April 1999, p 19, Institution of
Chemical Engineers, ISSN 0260-9576.