Hello,

Just received the UP 844 37984 and I am impressed. It is a supermodel!

I have 3 questions about it:

1- In the manual it is written that the smoke fluid must be 02421 (the 250ml "bottle" for gauge I locomotives). Is it different from the
usual 02420? (I ask this because at the moment I only have with me the 02420 and so I may need to buy the 02421).

2- The small pipette is not graduated, so, how can I know when the amount of fluid is 1,5 ml? (I mean approximately by looking at it)

3- The pair of small green lights and small red lights in the back of the tender are not functional, I mean they don't lit. Is it this way?

Regards,
Miguel

Wrong. Not all smoke fluids are identical. I know that ESU make a smoke fluid for use in their diesel locos that is required for proper operation of the smoke unit. 'Normal' smoke fluid doesn't work and clogs up ESU smoke units.

I suspect the 02421 smoke fluid has a lower viscosity so that it can be pumped somehow into the smoke unit, or reacts quicker to turning the smoke unit on. This would correspond to G1 locos having synchronised smoke for some time, which is now making its way into H0 models.

I would think that if you use 02420 smoke fluid you will not get the pulses of smoke that is so dramatically illustrated in a video on this forum.

Sorry! I wonder if Suethe makes it for them? Maybe I should try it out on my 37080 br10? Doesn't smoke well. New unit too.

I have an ESU diesel with dynamic smoke and I only use their specific smoke fluid. I also bought a decent hobby syringe that lets me add the specified amount of fluid, since bad things can happen when these are overfilled. These are significantly different smoke units than the old style ones, which would vaporize pretty much anything you put into it. Therefore using only the specified smoke oil makes sense to me.

I think that similar measures should be taken to get the best out of the UP 844 and its dynamic and synchronized smoke, which is a key feature. If mine functions like that one starting up in the video I will be very happy.

Interesting about the marker lights on the tender. My Challenger has them and they do function, but I guess that is not necessarily the case for the 37984.

The marker lights working for both of my Challangers,the difference is that there is not green color,only red.

I just was on the ESU site. The only smoke fluid listed is the 51990. No search result for the 02421. They say it can be used in all of their smoke units.

Did you even read anything other than the first post in the thread?

As far as I am aware ESU has only ever made one type of smoke fluid, specifically for their smoke units (although I am sure it will work in other smoke units as well as they claim).

Have you checked the Materials Safety Data Sheet for each of the items? I cannot find an 02421 listed in the Marklin web site, but the 02420 data sheet has an MSDS attached that is quite illuminating. The oil is made by Seuthe for Marklin, and has around "80-90% Hydrocarbons, C11-C13, isoalkanes, <2% aromatics" which on reading the Wikipedia page on kerosine would suggest this is the kerosine content, with the other 10-20% "Petroleum Distillate", so it is more than just kerosine.

But it is also quite clear that the ESU one is different. The description on the ESU web page clearly says that it does not leave an oily residue on the loco (which the Marklin one always has, and after a bit of use it gets quite noticable), but they do not have an MSDS that I could find, so cannot verify what it uses. I suspect it is more like the fluid used in smoke generators for social events and the like that use a water based fluid. I'll have to hit up the club members at the MRR club I go to for an MSDS for the smoke fluid they use in the model of the Didcot Power Station which uses such a smoke generator for the steam coming out of the cooling towers.

Maybe there is a reason I can't find 02421 on the Marklin web site, it appears it may have been discontinued. Eurorail Hobbies report it is "no longer manufactured" and the sites I could find an MSDS for it they were only in German (where the 02420 has both English and German on the Marklin web site). It seems the only difference between the two catalogue numbers is the size of the bottle (250ml for 02421, and 50ml for 02420) as the MSDS sheets have the same issue date and revision number, and appear to contain the same chemical makeup.

I haven't checked the LGB oil for an MSDS. I'll leave that for someone else to do.

As you suspect, the 02420 and 02421 have the same datasheet. But they are probably mixed differently, since the datasheet gives quite round figures on the content and boiling point etc. The 02421 is available on the Marklin webshop, and it is the same as 02420, and it's also specified in the datasheet itself. (different file names, but the same content)
On the LGB site, the 02421is listed as in stock.

As for the price, the 02421 is a lot cheaper per 100ml, than the 02420. 02421 is €9.99 vs 02421 thas is €21.98 (100 ml). But I never assumed i would buy a 250 ml bottle, it will probably last a lifetime for my needs. An interesting question is, does the 02421 bottle prevent evaporation? Some of the content in my old 02420 bottle has evaporated.

interestingly the ESU 51990 data sheet lits it's contents as: 90 – 95% Alkane, C11-15-Iso Cas-No. 90622-58-5, and 2 – 7% Terpenkohlenwasserstoff
Cas-No. 8028-48-6.

so in order to summarise a bit:
so the interesting question is, will 02420 work in dynamic smoke generators ?, Probably, but not as well.
Is there a reason for Märklin to specify 02421 ? Probably yes. a lightweight oil will probably work better in dynamic smoke generators. (as mentioned other posts)
Are there any long-term issues with using 02420 dynamic smoke generators ?. I don't know. I know too little to conclude.

I have the same problem with the vials supplied with Seuthe smoke units. Some i have had in stock for a while have lost a significant amount of content despite still having the foil seal. clearly the plastic bottle is quite porous to the smoke fluid. Maybe one should decant it into a glass bottle on arrival and use a lid that seals better than the Seuthe one.

I'm intrigued that you could fine it in the web shop and on the LGB site but it's not in the Marklin catalogue pages.



Is this from a printed copy, or did you find a downloadable sheet somewhere?

probably a bug somewhere.....?

Decanting it might be a good idea. I Have also noticed that some old 0241 (yellow box of 5 tubes) I have, still is as good as new but some "newer" ones are almost flat. So far my ESU bottle does not seem to have evaporated. but haven't marked it so I can't say if it evaporates less or not at all.



it can be donloaded from lippe: https://www.modellbahnshop-lippe.com/Accessories/Smoke+generators/ESU-51990/gb/modell_71900.html

The red/green marker lights on the sides of the tender do not work, and they are designed that way. Ref: https://www.stummiforum.de/t196897f2-Maerklin-UP-1.html#msg2346300

another nice little feature on the 844, is the small hatch on the cab roof that can be opened

Here is a tip for those who are interested, and of course at your own risk etc.

in my 844 37984, I did find that the background steam sound, was set a bit high from Märklin (but prototypical). but I did find that it drowns the other sounds a bit.
with "background steam sound" I mean the steam sound you hear after enabling "running sounds" and the locomotive is standing still. or Grundrauschen in German

Found out that it is possible to change that sound level separately, if you have a cs2/cs3 and mDecoderTool, and are willing to update the original sound project.

Here is how:

1. download the 844 decoder project from Märklin

2. when it is open in the mDecoderTool, go to the sound page and double click on running sounds. scroll down to "Lautstaerke Grundrauschen" and adjust as preferred. (i tuned it quite a lot down)

3. transfer the complete project via CS2 or CS3 to the decoder, when the locomotive is on the programming track. NB! this takes around 45-50min, and must not be interrupted.

the setting is not stored as a normal decoder setting, but as part of the sound configuration, so settings and sound need to be transferred.

more on how to connect cs2/3 to computer etc, and mdecodertool are covered elsewhere on the forum.

the "Lautstaerke Grundrauschen" setting is only available in recent models e.g. in 39027 and 39480, and e.g. the 39436 s3/6 Hochhaxige does not have that setting.

It's not possible to change this with a c.v, this is the only way. (according to Marklin support).