How do you know what size your Rail is

[Peaky Rider]

Apart from the sticker on the frame, is there a simple, foolproof way to confirm what size your bike is?
My Rail 7, size M, feels considerably shorter ( more upright) than my medium Focus Jam2. So much so that I'm starting to wonder if they stuck the wrong sticker on it.
The 'reach' is supposed to be about the same, but I have never really understood what the term 'reach' really refers to.
The distance from the centre of the seatpost to to centre of the head tube is 2 to 3 cm less on the Rail compared to the Jam.

 

[Aikone]

Ask a Trek retailer to check the frame number on the dealer website, it’ll tell them what size, colour, year & list out all the correct spares.

 

[Voluptua]

The one dimension on the Trek sizing diagram that seems to be bulletproof is the seat tube length. All the others go out into fresh air, or are dependent on fitted components.