LuaTransportLine linear length

[sparr]

I'd like to know how long a transport line is so I can calculate how many items will fit on it. Based on my experiments I think it will be approximately as follows:

32 straight belt
40 curved belt outside
16 curved belt inside
16 visible part of underground belts
?? underground part of underground belts
16 each of the eight lines (4 input, 4 output) of a splitter

[boskid]

In 2.0 there will be LuaTransportLine::line_length.