I use a siatek throttle quadrant to drive the trains in TS, at the moment i use the 'Cobra One' joystick interface to make the joystick work in train simulator... because it allows irregular notched levers mostly.... but TS_Fireman and the TS_Conductor is probably fine too.... i do want my joysticks to work over TCP though, so will probaly switch over to TS_Fireman one day.
However, it is a little 'weird' using the knobs that comes with the throttle quadrant, as they are designed to replicate an aircraft's throttle and fuel trim levers... obviousely.
But for a few euro's and a little time you can make them resemble the levers found in German Trains:
First you need the knob tops... Ebay is where i got mine from... sorry, the link is to ebay UK as i live there :
M8 Tapered Knob
But you can probably buy these in those amazing DIY stores you have in Germany... like OBI, Praktika etc (can you tell i miss Germany... UK DIY stores are so small in comparison)
Anyway, you want some knobs that have M8 threads in them, the tapered knob for the 'power' and 'AFB / Dynamic Brake' measures:
24mm at the top
18mm at the bottom
33mm tall
They are used on JCB's, Diggers etc, and i found this size to be just about right for the throttle quadrant... but you could go for larger M10 threaded ones if you wanted... just be aware they might touch when all levers are together.
The round ball knob i had in my junk drawer, but it is about 40mm diamiter, and again ebay sell them, or a DIY store likely has them too.
Then you want some M8 Threaded Inserts these are usually used for screwing into wood.
And also some M8 threaded bar, or bolts you saw the hexagon head off, to fix the knobs to the threaded inserts.
And lastly, some 15mm plastic pipe... in england it's called 'barrier pipe' or 'Hep2o' or 'PolyPlumb' etc, it's that stuff that's replacing copper pipe in house plumbing, you need about 300mm of it...
Sorry again, it's a uk ebay link to where i bought mine :
Plastic Pipe
And finally something to make the pipe black if you want (my pipe was grey, but it's usually white, you may be able to buy black pipe of course.
You can use black paint, or black vinyl (sticky back plastic / Fablon) or even electrical tape can be used to wrap around the pipe to make it black... or leave it white / grey if you like.
To put this together, cut the plastic pipe into 3 lengths... i chose to make the brake lever the tallest at 130mm, and the AFB / Dynamic brake lever the shortest at 80mm, and the power lever was what was left from the 300mm length of pipe. but make them what ever lengths you want, you are customizing this to suit you.
Then screw the threaded inserts into the pipes on one end... so 3 x pipes, 3 x inserts, and they will look like this:
Screw the threaded bar into the end of the knobs, cut it so there is about 20mm or more sticking out the end, and screw the knob in to the pipe.
NOW this is importiant... you need to squeeze the open / bottom end of the pipe in a vise or similar to make the open end slightly oval... so do this before you put any paint or vinyl on it to avoid marking it:
This is needed to make the new train style levers grip the shafts of the throttle quadrants oblong shaped bare levers, place the new train style lever's over the throttle quadrant's bare lever shafts and twist 90 degrees, that's the reason for making the the pipe oval: it locks the train levers onto the throttle quadrant's shaped shafts.
The AFB / Dynamic brake lever's knob shape.... you may be able to buy knobs with the 'scalloped shape' but i used a round file to put the indents into a standard tapered knob, you can see i didn't do a very good job getting the 8 bits i filed lined up, i will try harder next time 
I hope this is useful to someone, it's so much better to drive the trains using levers than the keyboard, and not everyone has the space for a replica driving desk, or can afford a raildriver.