About Sihl 4

We are a competent and excellently networked consulting firm specializing in technical safety in the railway sector. We support our clients in introducing new technologies and methods to the rail industry—from the conceptualization and development of specific products and railway facilities to approval and safe operation—always focusing on technical safety, interoperability, and cost-effectiveness. We represent our clients and their interests vis-à-vis industry partners and authorities, as well as in shaping the future within international bodies.

What we offer

Sihl 4 AG provides expert consulting, precise analyses, and practical solutions for safety-critical rail projects. Whether it’s RAMS management, OT security, or approval procedures, we assist you with comprehensive expertise, years of experience, and a clear focus on feasible, standards-compliant, and economical solutions. Our goal is safety that works.


Sihl 4 AG is based in Zürich – perfectly placed and perfectly connected to the railway sector, on a national as well as an international level.

You reach us with utmost convenience with every means of transportation:

  • Tram: stop Stauffacher, served by lines 2,3,8,9 and 14
  • Train: Zürich HB, exit Europaallee and a short 8 minute walk
  • Airport Zürich: direct connection (13min) to train station Zürich Wiedikon, from there an easy 5 minute walk by foot
  • Car: A3 exit Brunau, then, atop the river Sihl, in direction Wiedikon
  • Canoe: pull your boat ashore at the left bank of the Sihl next to Stauffacherbrücke, then some 3 minutes by foot

Contact options

 contact@sihl4.com
 +41 43 200 04 42