April 13 (Reuters) - Castellum Ab CAST.ST
* Castellum and Heimstaden enter into major transaction totalling SEK 2.4 billion
* In all, the transaction comprises 27 properties, totalling 186,668 sq. m. in Norrköping, Linköping, Örebro and Solna Source text for Eikon: ID:nWkrdm3442 Further company coverage: CAST.ST