@Gregor
I have accumulated a lot of close up pictures from frogs point ect, mostly from The Netherlands and the Soviet Union around 1950.
Soviet (1920-1960) is what i am going to model and the Dutch railway was interested(1920-1950 and 1980-2000).
As i stated before our railroads are pretty much the same design, i am for 95% sure.
Before 1960 i am almost 99% sure.
Before 1945, more questions than answers:
If you are modelling a area before 1930, than the dutch railway will not help you, instead look for British railway? but this i am not really sure.
My knowledge about the
German Empire regarding railroad is not much
.
How ever there where efforts i thought between the Emperor and Lenin and Stalin.
I am sorry i am not able to help you with this time frame for your country, only with things I had a quick read on.
I also thought the British where involved heavy in the development in this time frame, after Lenin there where some changes i thought.
Mostly for the demand of freight, the building of coal wagons exploded in 1922-1925 and even that bad they had to order them in Poland in 1930-1932
Back to today.
The main changes in appearance thru the time frames is the height of the track, lengths and shape of the safety rails, incl the frogs.
Now add some engineers from different country's and you will see that there are all made for the demand of that particular line/country.
For my feeling is around 1970 in Europa (U.S.S.R around 1930's and the US of A around 1900's-1910's) the difference between commuting tracks and freight tracks really separate.
Trains are getting faster, longer, heavier and commuters want more comfort, both want to have more speed, etc.
How far you want to go in this subject?
If i compare pictures from Nuremberg tracks from around 1980 before they where replaced they look very similar to the Dutch track work.
I hope this helps?
Anyway what time frame are you modelling btw and more important how far you want to take it into detail.
Maybe i can give you a better and more suited answer instead of a global answer.
For rail cross sections i can not be of assistance. BH FH ect.
I can imaging TT scale will be indoors and at 1 meter high, so details are going to be very important?
With best regards, Igor
Ps The corner of the Chinese/Japanese tracks are a different world with a second look