I sometimes see a lot of uninformed talk about Delta, even some calling it Marklin's greatest flop. The truth is quite different!
When Marklin came up with the digital system in the mid '80s, digital locos cost about 50% more than the equivalent analogue ones. Add to this the considerable cost of the digital controller, and we were looking at a rather heavy investment.
In the early '90s, Marklin decided to try to minimise the cost of making the jump to digital. Delta did this by addressing the two main costs in the process, the controller and the loco decoder.
Essentially, Marklin looked at delta to provide the essential function of a digital system, to be able to run more than one train on the same bit of track. To do this, they came up with the delta control, which allowed you to control 4 (later 5) locomotives digitally. Four addresses from the 80 available in the digital system were allocated to the delta system. Any digital or delta locomotive could be assigned those addresses, which meant that a small to medium layout could easily be run digitally with the delta control. To keep the cost down, there was no provision for functions, computer control, etc, although the last incarnation of the delta control, the 4F, had the F0 function button, allowing you to switch the loco lights on and off.
On the decoder side, they again looked at keeping the cost as low as possible, and the original loco decoders had 4 switches (or solder tags on the earliest) to be able to select one of the four delta addresses. In fact they also allowed another 11 possible addresses which could be used with a full digital controller. The lights could not be switched except on the very last series, the 66032. No other functions were provided, except that on the last models there were connections for Telex couplers.
As for the standard of control and running qualities, there was no difference between a loco with a 6080 decoder controlled by a 6021, and a Delta loco driven by a Delta control. The main limitation in both systems was the poor low speed running of the AC motors under digital control, and the lack of load control on the decoder. To address this, Marklin came up with the 6090 decoders and 5 pole DC motors in their 37xx models, which ran just as well on the delta system as on the full digital, but were obviously more expensive.
For me personally, Delta was a great success. By buying a starter set with a Delta 4F controller, I got into the digital world relatively cheaply, and eventually I made the simple upgrade to a 6021.
Delta locomotives, which cost no more than analogue ones, were a good choice for expanding my loco fleet, and even though I have converted many with high efficiency drives, I still run quite a few with their original delta decoders.
I am a firm defender of delta from it's critics, and this is because for me, as I'm sure for many others, it allowed a transition to digital which I might not have been able to afford otherwise.
Ray
