Hello,
There are some vehicles in openPAK that have their power, weight or/and introduction dates wrong. Here's a list of some of those vehicles for reference purposes. On some vehicles, which seem incorrect for era or otherwise just "wrong", I've taken liberty to speculate on what's going on with those. I'll update the list if needed.
Trains
CKD 750
In reality, this is a CKD 753 with different train heating system for p****enger trains - this isn't relevant in Simutrans so basically 753 and 750 are the same thing in the game. Introduction year 1968, power 1325kW, weight 73 tons, top speed 100km/h. Reference: http://www.skd.cz/EN/lokomotivy/T4783.htm
BR 218
Intro date in game 1954, in reality prototypes in 1966 and series production started in 1971. Reference: http://en.wikipedia.org/wiki/DB_Cl****_218
MJHN Deltic
Intro date in reality 1961, not 1966. Power 2460kW. Reference: http://en.wikipedia.org/wiki/British_Rail_Cl****_55
Road vehicles
GAZ-2
Could not find a prototype for this, but GAZ factory only began production in 1932 so intro date 1922 is too early. Reference: http://en.wikipedia.org/wiki/GAZ
GAZ-3
Seems weird, too. Look at following and previous entry...
GAZ-4
Introduction date matches real-life GAZ-03 but vehicle is very different... GAZ-03 capacity is 17 p****engers and power 37kW. Top speed 65km/h. Reference: http://www.autogallery.org.ru/gaz0330.htm
PAZ 672
Introduction 1968, not 1936. Power 85kW, top speed 80km/h, empty weight 4.5 tons. Reference: http://www.sovavto.net/PAZ/672-E.HTM
PAZ 772
Could not find prototype for this either. Anyway, too powerful and looks like something from '60s instead of late '30s. Is this supposed to be a city bus or a liner?
LIAZ 677
Introduced 1967, power 134kW, top speed 70 km/h, empty weight 7.8 tons. Reference: http://www.sovavto.net/liaz/677-e.htm
Ikarus-260 liner
Had hard time finding a prototype for this, but Ikarus 259 may be right. Way too heavy, 9 tons seems right. Many different motors available in 140-170kW range, top speeds ranging from 90 to 120 km/h, introduction date about right. Reference: http://www.freeweb.hu/buszok/ik259.htm
Ikarus-260
Most powerful engine option was 162kW. Reference: http://pl.wikipedia.org/wiki/Ikarus_260
LiAZ-5256
Introduction date 2000, not 1979. Real power 180kW. There was apparently a slightly different-looking model that was made from late '80s, but I need to find better data on it. Reference: http://www.autoevolution.com/trucks/liaz-5256-2000.html
Got the list. I will check the vehicles and change data when appropiate. Thank you very much, onre!
Some of the data might have been altered to make the game playable...
Sure, that was explained via IRC. Of course vehicle's data won't be modified if the modification has a severe impact over the vehicle type timeline (specially sensible for intro/retire dates).
And some vehicles were added not based on their realistic dates but based on their speed for the timeline speed bonus, I think...
That's why some slow (RL) 1990s stuff appears in game as early as the 1960s...