The HAJDE team witnessed this event while travelling with U1 in the direction of Oberlaa. This smell soon led to a large-scale fire-enforcement operation at the U1/U4 subway line interchange at Schwedenplatz. 

The station was evacuated after a suspected smoke development was reported. However, this turned out to be a false alarm. 

The fire department spokesperson, Jürgen Figerl, told MeinBezirk that they were alerted to the situation around 11 a.m.

"We received a report of smoke," he explained. As is standard procedure in such cases, the station was immediately evacuated. All trains were also stopped.

In such cases of alarms around subway stations, a very large number of firefighters are routinely deployed. In this particular incident, three fire crews with their associated vehicles were involved.