I don't know, obviously, but it is an odd arrangement, that I have only seen on the military versions, that I remember.
If they want clean intake air, then putting the intake pipe up at the same level as the exhaust pipe is an interesting choice.
I'd better check my files on the civilian 406 Rail UNIMOGs, because if they never show this modification, then
that begs the question : what environment do the Military versions work in that the Civilian versions do not....?
I mean, a rail yard is a rail yard, no matter if there is OD paint on the equipment or not.
I think I have a photo of one of them in a book - maybe I can find it and translate the caption for an explanation.
I went through the Civilian 406 Bahn file, and although I found some with the elevated exhaust, nothing with the snazzy snorkels.
The yellow one with the DOW logo on the door has the next-weirdest array .
There are a few 416 military versions, and they don't match the weird ones either. Of course, some of the 416's are from the Italian Army, so I would not expect them to match the German approach anyway.
OK, I believe the answer is in this blurb. It mentions the Exhaust (Auspuff), Engine Intake (Motoransaugung) and the Compressor Intake - ((Suction pipe))-(Ansaugleitung der Kompressoren), and a Flameproof pipe coupling system.
The three things mentioned would be the three things with the odd snorkels, ergo, all three systems have an enhanced Flame-proof system of some sort.
Perhaps the Military is working to a higher standard of safety than the civilian system, which is why these devices do not appear on the Deutsche Bahn UNIMOGs. That could be because the Military UNIMOGs shuttle around things like Munitions, perhaps ?
These Military Rail UNIMOGs seem to be centered around Westerwald - I wonder if there is a Bundeswehr Facility there that might be a Munitions Production or storage facility ?
Ah...I just checked and the Artillery Battalion 350 has been based in Montabaur since 1965, at the "Westerwaldkaserne". I'm not ready to wade through the translation, but "Nuklearen Teilhabe" (Nuclear Participation) and "Atomwaffen"
(Nuclear Weapons) appear in the article about that place.
The one example I dug up of a non-military Zweiweg UNIMOG that had something odd (although not a dead match), has a DOW logo on the door. Working with Volatile Chemicals in a large Chemical Plant might require higher safety standards as well.
I do think that Munitions might be the key to the reason for the Flame-Proof systems on these UNIMOGs. I'm not clear on how an intake is a flame risk, but they have a reason for their caution, no doubt.
They might not have anything to do with this specific base, but they are involved with something in the Westerwald, or they were.
That military base is a solid red herring. Closed down, it has been converted into a housing project. Plus, there is no rail yard in evidence.
There is some connection to Westerwald with these UNIMOGs, as that location is often mentioned in the captions.
"MUNITIONSDEPOTS" are mentioned.
The Westerburg Station is closed and is now part of a museum.
I think that while the UNIMOG two-ways were used to shuttle general military loads around, they were equipped with the odd snorkels, which are part of an enhanced "Flame-Proof" system, for extra safety when munitions were involved. The newer U417 UNIMOGs show the same system in place.
I'm thinking that they are a type of anti-backfire (intakes) and after-fire (exhaust) traps, and they prevent open flame from occurring under any circumstances.
While a diesel engine is unlikely to backfire, it is not technically impossible, and they must be working in an environment where any flame could be dangerous.
I think that is a better description than the "flameproof pipe coupling" that I got using online translation. Technical terms don't always translate well, even from German, which tends to string together a series of short (sometimes) descriptors into compound words.
If it does not rain later today, I think I should attend to a little Aufgangsreinigun, myself.
If they are concerned about open flames on their UNIMOG rail Shuttles to this extent, I wonder if all of the support vehicles - forklifts, freight trucks, etc., are similarly equipped ?
I found a US Army document of 344 pages, dated 2011, which pertains to all aspects of safety in a munitions depot:
'Ammunition and Explosives Safety Standards, Dept of the Army Pamphlet 385-64.'
In section 2-17, it addresses material handling equipment. Electric Forklifts are recommended, and they are broken down into specific types, some of which are rated to be used in places where 'Explosive Dust' is present, many of which are not.
In regards to 'Gasoline and Diesel powered equipment', it reads that they : 'will be equipped with backfire deflectors securely attached on the throat of the carburetor. These deflectors will be of the oil-bath or screen type. Certain types of air cleaners can serve as backfire deflectors. /
A flame arrestor will be installed on the fill pipe. etc. etc.'
Anti- Static Electricity systems are also part of the equation.
And, so, in the end, 'A rail yard is not a rail yard.'