Greetings James
Thank you for joining us on this great forum.
Here a Märklin fan from Paris - France

What is DELTA:
- it is a Märklin brand to designate a simplified digital loco.
- it was used 20 years ago during many years (no brand new Delta anymore)

What simplifications?
- a reduced number of possible addresses (often limited to 4 or 5)
- no indepedant fonction(s) like lights, Telex, etc
- lights are dependant on the speed (faster = brighter)
- no inertia simulation
- no sound

Cheers
Jean

Welcome James. Yes, you can run Delta decoder equipped locos with any of the Marklin digital controllers. The first Delta controller had a 4 position switch, for a steam, diesel, electric, and a railcar, but not exclusively for one of each. Just 4 addresses.
It connected to the blue former transformer. A Delta pilot corded extension control came next, to allow a second person or to run two trains at once. It had a speed control knob and a reverse button. I made my own with a blue project box, red button, and potentiometer from Radio Shack. The second Delta control was white and added a button for the headlight function. Also the starter sets initially came with a fixed address decoder, but later delta locos have a dip switch decoder with 4 switches which adds additional possibie addresses. As my collection and layout grew in size, I upgrade to a 6021 digital controller, then to the MS2 and a CS 3 plus.

To say that Delta is not used today is not strictly true. While they are not labelled as Delta the joystick and infrared controllers used in start sets use the identical loco addresses for the four selectable locos as the Delta addresses, and in most cases the locos supplied by Marklin have their MM address set to the appropriate one of these address for the loco type.

To expand a little on Jeans explanation, the Delta controller had a selector switch that designated the type of loco that was to be controlled, namely steam, diesel, railbus, electric.

Each class was allocated an address; -
Steam, address 78
Diesel, address 72
Railbus, address 60.
Electric, address 24.

The earliest DELTA controllers could also have an additional handset that had a dedicated address of 80, although use of this never really seemed to catch on.

Locos were supplied from the factory with the MM address already set to that appropriate for the loco type, so for the end user the system was very 'plug and play', take the loco out of the box, put it on the track, select it from the switch and away you went.

The addresses are a sub-selection of the full MM (Marklin motorola) address range and can be driven by any controller capable of controlling Marklin decoders.

The original Delta decoders had no functions available, but as they used the same chips as standard decoders people worked out how to add the headlight function. Later Delta controllers had a button to control headlights. Some of the current Start Up controllers do have up to four functions controllable plus the headlight.

That is right. Delta, as brand and as technical way, has been discontinued.
IMHO delta disappeared from catalogue at the moment that the PIC decoders were introduced, and the StartUp controllers with plugin power supply unit imposed by EU rules. At that moment they did the step to abandon all analogical and semi-analogical locos. (delta was the solution to replace the relais by some cheaper electronics and on the same time to offer a cheap entrance to digital railroading.)
But, effectively, remain some details, so as the MM addresses that can be piloted by the joystick controllers you may find in some "StartUp" starting packs. I suppose that this is because Märklin wants to maintain compatibility with some old delta locos to be found at the grandfather's house... so as any new loco may be controlled with a 1960s transformer (except if the manual says you shall not).

Since some years, there are some people that call "delta" all decoders with microswitch address coding, which is simply stupid since they throw in the same bin the c80, delta and c90/c90x, last but not least since they were the 1st class decoders for a couple of years with a really good motor controlling, and besides the antique MM or MM2 protocole, they hold very well their place face to modern decoders.

I recommend this site for more information on Delta/old digital decoders: http://www.pallund.dk/digiview.htm
including this page with various enhancements etc, including how to program 80 addresses on a delta decoder with 4 dip switches.
http://www.pallund.dk/convert.htm

This is not correct; FYI Märklin still produces and sells the 66471 transformers.

Nowhere in the EN IEC 62115 is it mentioned that transformers can't be used by children,
actually there's a note in the latest version from 2020 saying:

"Transformers for toys (EN 61558‑2‑7:2007 for linear types or EN 61558‑2‑7:2007 and EN 61558‑2‑16:2013 for switch mode types), battery chargers (EN 60335‑2‑29:2010) and battery chargers for use by children (EN 60335‑2‑29:2010,Annex AA) are not considered to be part of an electric toy even if supplied with an electric toy".

Per.

P.S: Of course Märklin has a not required note in the 66471 description:

"The 66471 safety transformer is not a toy for children."

Unlike manufacturers and sellers of balloons who are required to mark their products with:

"Warning! Children under eight years can choke or suffocate on uninflated or broken balloons. Adult supervision required.
Keep uninflated balloons from children. Discard broken balloons at once."

I don't know; you started by telling us Märklin stopped making starter sets with transformers,
because transformers are not allowed in children's toys

What you've mixed up, and what you can see in the below found by yourself, is that a transformer is not allowed to be
an integrated part of the toy ( but has to be a stand-alone unit, as e.g. the 66471 )



Please show us where the law is that makes stricter rules for the Märklin 66471 than for any other household transformer.

Per.

Oh, this is low.
You should read the whole header:

I agree, the link in the header points to an obsolete version of the text, the actual text - in it's relevant version having legal effect - is here: https://eur-lex.europa.e...EX%3A02009L0048-20221205

But the cited text is the same.



From the moment you need to touch the transformer when playing with your train, the transformer is integrated part of the toy and must not be connected directly to the wall socket but to a PELV or SELV source.

Is that really so difficult, or just an attempt to keep reason against all arguments ?
'cause I give arguments, you say just "it's not that". Proove it! Give texts that say, with legal authority, "a transformer with integrated controlling unit is not a toy in the meaning of the toy directive".
That is the reason why a 66471 is not and will never be declared as toy for children below 14 years: it combines the controlling unit, which is clearly part of the toy, with the transformer unit. This combination is prohibited by 2009/48/EC.
And since you have access to EN IEC 62115 without paying 200 Euros, would you, please, verify the description given in EN61558 about "transformers for toys"?

This all seems a bit off topic from J's original question.

Hi J !

Just to add a picture with the address selection for Delta/Digital




Best Regards
Joël