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The 15xx series (Blankenberge-Genk) trains are either formed of M6 double deckers (https://nl.wikipedia.org/wiki/M6_(spoorwegrijtuig)) or MS96 (EMU with "danish noses" very similar to the I11 coaches).
The 23xx series (Oostende-Brussel Airport via Kortrijk) can drop M6, MS80 and MS08.
The 28xx series (Knokke-Brussel Airport) is either M6 or MS80 with an odd MS96 thrown sometimes.
If you are interested in formations of specific trains, http://www.beluxtrains.net/ has the planned rolling stock for all belgish trains (also of earlier years) and at least the beta of the HyperRail app (https://play.google.com/store/apps/details?id=be.hyperrail.android) is capable of providing realtime information including formation and numbers (but the NMBS data feed is not too reliable).
We are aware of an issue with emails from the Forum to Microsoft-based email accounts (hotmail/outlook/live.com email addresses). This is being looked into currently, thanks for your patience meanwhile.