YABBC (Yet Another BigBrother Cache)

At first I wanted to name this cache "Big Brother", but then I noticed that there are plenty of BigBrother-caches around, so this is just yet another one.
Why the name? You'll (most likely) see..

Please note: Some stages are (most likely) only available between 8 and 19 o'clock local time. You have been warned.
Basic mathematics are being used, each number of the coordinates is calculated on its own - no multiplications.
If you come by bike I'd recommend leaving it at stage 3.
Please avoid spoilers in your log and think again before uploading pictures, thanks.

Thanks to grizz-gps for beta-testing this cache (max. 45 minutes).

stage 1:
N47 05.595
E15 25.173
Too bad it isn’t there anymore. Here we need the second year on the sign (1abc) and the distance below (de0).

1abc =
de0 =


stage 2:
N47 05.(c-1)de
E15 25.ebc
Here we are interested in the first year of construction of a certain thing (1fgh), as indicated on the larger sign.

1fgh =


stage 3:
47 0(f-3).(g-d)(f-1)g
15 25.h(h+4)(c-h-d)
Getting this information is even easier than at the previous stages - no long texts waiting for you. What's the number on the house in front of you? Three digits (ijk).

ijk =


stage 4:
N47 0(f-3).j(k+d+1)f
E15 25.hk(b+i)
Someone left his thoughts on the ground, ending in "..atha." The two numbers next to it are what we are looking for (lmno). Be aware of the name of this cache and smile, even here.

lmno =


the cache:
47 0(f-3).(o+2)(f+i)(n+o+d)
15 25.n(c-g-1)(m-n-i)
Finally.
The cache is a small film canister. Please bring your own pen.