Oops,
I ment to say, "could there be a potentially dangerous electrical problem??"

The other issue with the blue metal transformers is that the insulation can break down over time, and therefore present an electrocution risk. Marklin had a transformer exchange program for some time, where you could exchange an older transformer for one of the newer white ones. I don't know if the exchange program is still available.

It's not regulated with current transformers either.

Märklin say that transformers with a nominal voltage of 110 Volts must not be used. This one is for 115 Volts.

The manuals for current locos say:
"Possible operating systems: 6646/6647 Märklin Transformer, Märklin Delta, Märklin Digital, Märklin Systems."
And:
"Use only transformers rated for your local household power.
Do not under any circumstances use transformers rated for 220 volts or 110 volts."

In general: blue transformers were made for analogue locos - and a few volts more made the reversing pulse more reliable.
Blue transformers for 220 Volts would be dangerous for current digital locos even on 220 Volts, so I avoid using them.

The blue transformer on the picture is rated for 115 V while the current #6646 is rated for 120 V.
So if your local household voltage is 120 V then the loco manual tells you not to use it.

Re: exchange programme
Why spend Euro 50 and postage for the old transformer when you can buy a new transformer for less than Euro 50?
This could be a good deal if you need a Märklin 6646, but the Märklin 6647 (230 V) is cheaper without exchange programme.

http://en.wikipedia.org/wiki/Mains_voltage

Many people in Germany still say 220 V while it's 230 V for several years now ...

Hello Ray,

As Tom pointed out, this is not a uniquely EU issue. But what´s more, every manufacturer worth its salt should have been able to update their products so as to tolerate a relatively small increase (or decrease as the case may be) of the supply voltage...

220V+10% (old standard)=242V, 230V+10%(new standard)=253V.

So, under the old standard, any mains-fed product should withstand at least 242V on the mains. Adding manufacturing, design and component tolerances and a proper derating of components used means that normally there shouldn´t be any problems with the 230V standard, not even with older products produced under the 220V standard.

Then again, some (decoder) manufacturers may be a bit skimpy or... simply "forgot" to apply proper component derating.. in order to save a few pennies may be?

Best regards from winter wonderland in Germany, Robert

Not for Germany: it was 220 V +/- 10 %, then for a transition period it was 230 V +6 %/-10 %, now it's 230 V +/- 10 %.
In the UK it was 230 +10 %/-6 % during the transition period.
So tolerance wasn't widened, it was restricted for a transition period.

A blue 220 V Märklin transformer running on 220 V can still kill an mfx decoder, so blame ESU or Märklin, not the EU.

EU could have gone for 230 V +/- 6 % allowing all old devices from the 220 V (+/- 10 %) and 240 V (+/- 10 %) era to be used within their specifications.

Back to original question: are they safe?

Is the warning part of the lawyer's list of warnings intended to make it our fault if anything bad happens? Or is the risk real?

Who knows for sure, though I suspect that it is the lawyers conjuring up risks.

I have a bunch of blue transformers (and a couple of white 6646s) that I use for an analog layout, and am happy with the result.

Bill

Last things first: the Marklin transformer exchange program was discontinued in the US about 3 years ago. I've exchanged about 60 of these for my customers. Early in 2009 I was told that (again, in the US) this program had been discontinued.

As for using the 6153 and other transformers, I've used dozens (maybe hundreds) of the "old" blue transfomers with countless digital locomotives -- both in analog mode and to power digital components, and with all types of digital decoders -- and have never experienced any problems whatsoever, even when using the "over-voltage" signal to reverse digital locomotives on an analog circuit. I've occasionally measured the voltage of this reverse pulse and it can go as high as 30VAC -- still, never had any problems. As long as the cable is in good condition, and the plug looks OK (which can easily be replaced if necessary), you shouldn't have any problems.