MINOR UPDATE [2017-05-20]
have just uploaded a cleaned-up sketchup file for anyone who want to make their own. had a bunch of duplicate components that was bloating the file up to 2mb.

MINOR UPDATE [2017-05-11]
v3 items removed. v2 should get you there.
ramp01 now has two formats 'print flat' which prints horizontal to the printer bed, or 'print in place' which prints as it would sit on the game table (45o). second option requires substantially more support but reports suggest that it prints much better. both options are available.

MINOR UPDATE [2017-05-08]
v2 risers and ramps modified to reduce clearance of connector pieces.
all 'double riser' connectors reduces as they created a gap between decks.
v1_ramp01 flipped over 180o to reduce print cleanup.
v3 added for risers and ramps. this creates a uniform 0.1 clearance in all directions where there is a connection (glueable). i'm not entirely convinced about v3.

MAJOR UPDATE [2017-05-05]:
new/updated models added.

based on suggestions/requests from people doing printing (thanks abchiptop).

work log...

• checked all decks same dimension (5mm thick) [x]
• checked filler01 and filler02 match the gaps in decks [x]
• check riser top surfaces are same and match gaps in decks [x]
• check riser width (vertical) as same (4mm width) [x]
• 'bottom level' risers reduced 'foot' by 2mm [x]
• double-sided riser top variants [x]
• riser05, riser02; increased all underside catches by 2mm [x]
• guard1a and guard1b; increased all underside catches by 2mm [x]
• ladder; increased underside catches by 2mm [x]
• handrail; increased all underside catches by 2mm [x]
• lowguard; increased all underside catches by 2mm [x]
• check ramp01 and ramp02 match the gaps in the decks [x]
• recess top bar of all risers by 2mm in all directions except underside (v2) [x]
• recess connection piece for ramp01 and ramp02 (v2) [x]
• reduce filler01 and filler 02 (v2) [x]

should possible emphasized that the terrain set is 99% meant for construction with superglue. it's not really suitable for just shove them together and hope they stick by friction. my intent when making these was to create 3-deck long sections (including risers and handrails etc) then sort of setting them all up end to end.

--------------- old notes ----------------

an example generic/very basic terrain set for making industrial gantry terrain.

IMPORTANT: i've been making several small changes fixing bits and pieces, width or so on, so i recommend if you're planning on printing these look back just before you start to get the latest. older version may be a bit wide or wrong.

haven't played with fitting tolerances at all so likely to be a tight fit (works as confirmed by Kolden. thank you very much! http://www.thingiverse.com/make:325293).
[later] have printed out a few bits and pieces but i'm not planning on making a whole table's worth.

the decks connect to the risers using the guard(rails). probably could make a cross beam to stop wobble (spacers, done) but this is mainly a concept work. most of the pieces are 3-5mm depth which is quite chunky but the intention was to make the bits snap together strongly and be fairly stable. being chunky also allows people to glue on their own bits and pieces, rivets, skulls, mesh, controls etc.

the deck and risers should be able to print flat as a single piece. for longer pieces of decking/gantry i envisage just super-gluing together multiple deck 'squares' into single, long, permanent pieces. i've added 'filler02' which is bigger as a theoretical connector piece.
the guard/connectors may need a bit more thought in terms of easy printing. keep in mind that there will be a little stress in the 'U' that connects deck to riser when selecting printing direction (i.e. grain).

as i don't play much 28mm anymore i'm unlikely to actually print this myself.

and finally i have my 60th piece!!!

[later] more pieces added. just variations and fixes mainly. updated sketchup file included

re pic 5...
shows the ramp connection from underneath. the ramp has a tenon that slots into the mortise on the 'deck' piece.
the mortise/tenon connections are used to join all the pieces together. the spacer01 piece is used to fill in deck slots that don't require risers or ramps.
the guard03 pieces are used to connect deck to riser where a guardrail is not required/wanted.