This one seems to have baffled the bureaucracy! During the first few years of the pneumatic postal system, only the use of the specially produced stationery was permitted. In 1899 the use of ordinary stationery was allowed provided that it was properly franked. However, a few such items did pass through the system without being challenged, years before they could officially do so. This normal 2 Kr stationery card of 1893 was posted in 1894. The card carries 8 Kr added franking to make up the 10 Kr rate.
This card is remarkable in that despite it being drawn to the attention of the postal authorities for carrying an invalid 5 Kreuzer Hungarian stamp, hence the manuscript "5Kr to pay - Hungarian stamp invalid", it still entered, and was transmitted by, the pneumatic system 5 years before this was officially allowed with normal stationery.
The card entered the pneumatic system at district 6, Wien 57 (Gumpendorf) at 3.40 pm and arrived at its final destination, district 9, Wien 66, Porzellangasse, nearly 3 hours later. This unusually long transit time was possibly because of queries over the invalid franking as well as over the destination. From the cancellations, it can be deduced that this initially might have been assumed to be Döbling, district 10 (from Döblingerstrasse) and then Wahring (district 18 as per address, Wien XVIII). However, the manuscript '66', written twice, indicates district 9, Porzellangasse, at the southern end of Döblingerstrasse.