I have just uploaded a set of revised base texts for what is now Simutrans-Extended (formerly Simutrans-Experimental) to Simutranslator. If anyone would like to help with translating Simutrans-Extended, there are now up-to-date texts with which to do so: see Simutranslator
to get started.
I hope to upload the updated pakset texts soon.
In the meantime, would anyone contributing to Simutrans-Extended's code please note that any new texts added to the game should in future be in a new base text .dat file (one for each set of new texts), as the old "base_texts_experimental-passenger-generation.dat", now having been uploaded, is deprecated. The plan is to keep Simutranslator more constantly up to date in future.
Finally, Frank, I should be very grateful if you could change references to "Exp" or "Experimental" on Simutranslator to "Extended" to reflect the recent change of name for this fork. Thank you very much.