Well, post them to me
Glad you're interested. Here you got: I posted both the drawings and some pics I could find of those models. In the drawings you'll find a variant of the articulated urban type, and the two short ones (called AC, both 3-door urban and 2-door suburban).
You'll notice that the articulated's drawing reads "suburban", but that's because all of those buses were officially classified like that. The drawing actually refers to the three-door version, orange in the pics, which was used mainly in urban journeys: there was a two-door version also (blue in the pics) which was properly used for suburban journeys, sometimes even on highways.
Some data you might find helpful (I'll omit dimensions as they're displayed on the drawings)
Capacity:
Seating 50 (3-door art.), 63 (2-door art.), 18 (3-door AC), 35 (2-door AC)
Standing 81 (3-door art.), 80 (3-door AC), 45 (2-door AC)
I still couldn't find capacity for 2-door art. Maybe you could figure it out with your method, consider it has 13 more seats than the one in the drawing (all of the seats are double and there's one more row in the place of the missing 1st door).
Power: 187 HP
Max speed: 68 km/h (both 3-door versions), 75 km/h (both 2-door versions as they were suburban)
Weight:
Articulated: 15,260 kg (empty), 24,400 kg (full load)
AC 2-door: 8,850 (empty), 13,770 (full load)
AC3-door: 8,630 (empty), 14,500 (full load)
Yes, those beasts were 4-axles buses, quite a unique feature. The engine was mounted on the front body and powered the 2nd axle.
Concerning the non-articulated versions, they were produced in two variants, the A (11-meter) and the AC (10-meter, in the drawings).
As for the years of production, the single 418 itself was born in 1973, but that bodywork (made by Macchi) was introduced in 1975, and the articulated version was released in 1977. All of them were discountinued around 1985 and had a life of about 19 years. I've got pictures of different bodyworks too.
The liveries were quite monotonous, i.e. orange with sometimes gray roofs for 3-door versions and blue with gray roofs for 2-door versions. There were some AC 3-door's which were painted red or deep orange in the bottom part (below the windows) and white or cream in the top part, though.
Now for the R312.
Length: 11.999 meters
Width: 2.5 m
Height: 3.109 m
Length in front of front axle: 2.17 m
Wheelbase: 6.12 m
Length behind rear axle: 3.16 m
Weight: 11,450 kg (empty), 19,000 kg (full)
Power: 206 HP
Capacity:
seating: 28 (3-door), 31 (2-door)
standing: 80 (3-door), 70 (2-door)
Production: 1985-1997
Life: about 20 years, still in service now
Do you think a side picture like this could help you? (attch)
Cheers!