For those who wants to model the German high-speed railway network (read: ICE), the ballastless track system is a common feature on certain stretches, one of them is the Frankfurt-Köln strecth with 4% gradient. In this website Project VDE8 (Projekt Deutsch Einheit 8), the construction of the ballastless track system is explained and illustrated. This will help you in modelling the system in your preferred scale.
Source: Project VDE8
germaN:160 by traiNmaster 
The new Kato Unitrack V 17 “Concrete Slab Double Track” matches this very closely.
http://www.ebay.com/itm/UNITRACK-Variation-Set-V17-Concrete-Slab-Double-Track-Set-Kato-20-877-N-scale-/121148446137?pt=Model_RR_Trains&hash=item1c350295b9
You could even use the Kato single track catenary masts to mimic the concrete masts used on German Neubaustrecken, just chop off the top part and paint them appropriately.
I’ve been thinking of making a little diorama of Limburg Süd or Montabaur for my ICE 3 to zip through.
MK
Yes, Kato and Tomic produced concrete slab double tracks. Thks for the link, Misha.
Looking forward to see your little diorama. Do you have a blog or posting in some forums? I am using http://www.stummiforum.de/
Not yet. I just moved to a new place and am still figureing out the basement space that I will use. We’ll see when I finally get around to starting proper construction. I have a 3-year old and a second one on the way, so things may get delayed… 😉
MK
Then I congratulate you in advance on your second one. Btw, where do you stay? Perhaps when you are ready to start, I could come over at times to assist you in building yours.
JL
Hi JL,
Thanks for the congratulations and for the offer. I was born and raised in Germany but now reside in Chicago. You’re in Germany, no?
Misha
Misha,
Yes, I am living in Frankfurt.
Jimmy