Simply using the translation file in reverse might however be easier than switching language in Simutrans.
While Object names are unique, translations are not. A simple "Catenary" might be the translated name of many different catenary objects.
Though a similar issue exists with simply switching language. Citybuildings don't display their object name, so they would need to be found in the "build citybuilding" dialog by finding a matching graphic.
For townhalls, you need to build a station next to them while having the correct station naming convention activated and playing in a language that did not translate it.
While it's possible to get most object names from the game, a dedicated tool ingame would be nice. Eg. click on any object to open a dialog containing at least the objects name and translation for the current language. If it's a tool, you require a menu that enables it, so normal players simply won't have it. But editing the menuconf to enable it is simple enough for anyone in need to see object names.
(Personally, I'd extend such a tool to show as much information about the object as possible, but that might get too close to "unpaking pak files" for some.)