After transporting 3 of the 1400mm (55") rails from place to place for a few years without protection, I broke down and bought two of the cat 466 357 guide rail tote bags.
I was in the process of building my new shop when I finally bought a set of Parallel Guides with Extensions. Since I personally no longer work on sites, I have not worried about moving my parallel guides.
One of the cabinet makers working for me still does some site work. For 20 years he was a foreman with an entertainment carrying and transport case maker in the Los Angeles area. Of course he has Systainers for his many Festools, but he also has a large collection of rock & roll style ATA cases for his other tools which do not fit in Systainers. All his ATA cases have red ABS exteriors. One of those holds his parallel guides and extensions securely. He also has a similar case for guide rails up to 1900mm (75").
Years ago I signed the requisitions for hundreds of ATA cases and I bought one for myself. Trust me, Systainers are a bargain. I hope my guy got a swell discount on his.