Arnold Digital 1

Although there had been other model railroad command control systems (such as Hornby’s Zero 1), it was Märklin that made the world safe for advanced digital model railroad control.  Their general concept was first shown by Märklin at the Nürnberg Toy Fair in the late 1970’s. By the mid-1980’s, Märklin Digital was introduced into the European model train market for their three-rail, AC powered H0-Scale trains. The following year, Märklin Digital was introduced in the North American train market.

Märklin went about things as would be expected from this large company.  The Digital systems had a clean appearance. The components were modular; the central unit was literally at the center of the control devices such as throttles and solenoid device controllers. This approach had precedent.  Märklin required that their dealers take training courses prior to being able to sell the units. In short, Märklin wanted to make sure that Digital would succeed and that their customers would be satisfied with the purchase.

The limiting factor was that Digital only worked for Märklin’s H0 trains.  While these were very common in Europe, they were not so common in the rest of the world, which prefers DC powered trains.  Likewise, other model railroad scales were left out because of their DC design. So, sometime after the introduction of Märklin Digital in 1985, Märklin contracted with Bernd Lenz to design a DC Digital system.  It was this system which would be the antecedent for today’s Digital Command Control (DCC).

In addition to the Märklin Digital DC product line, Arnold Digital was also manufactured using Lenz’s early standards. Arnold also used the same circuit board cases as the Märklin products, but with Arnold Digital lettering:

As with Märklin Digital, both the AC version and the DC version, a power supply was connected to the device and the additional controllers were plugged into the sides of the 86028 Central Unit N:

Up to 10 86035 locomotive controllers could be plugged into the right side of the Central Unit N.  Up to 16 86040 Keyboards, solenoid controllers, could be plugged into the left side of the Central Unit N; each solenoid controller controlled 16 devices such as turnouts and signals, making for a total of 256 devices.  

Four of solenoid devices were controlled by each 86078 decoder:

The 86078 was assigned a unique address by pressing both the appropriate button on the 86040 Keyboard and the “code” button of the decoder. For purposes of programming a series of 86040’s and their corresponding 86078’s, each Keyboard has a unique number in relationship to the 86028 Central Unit. If there are three Keyboards, they are 1, 2 and 3 respectively.  Each Keyboard controls 4 86078’s.  They are 1-1, 1-2, 1-3, 1-4, 2-1, 2-2, 2-3 and so forth.

The 86028 was rated at 2.5 Amps, which could easily be exceeded on larger model railroads with many locomotives and solenoid devices.  So, larger model railroads were divided up into power districts, each consuming less than 2.5 Amps.  Each power district was controlled by the 86015 Booster:

The individual 86015’s were connected to individual power supplies, and then were joined by a series of ribbon cables back to the Central Unit N. This ribbon cable carried the DCC signal from the Central Unit N, and each 86015 sent power and DCC signal to the different power districts.

Also needed was the 86030 Programmer, which was used to program locomotive addresses:

The 86030 was used in conjunction with the individual locomotives, each with their own unique address.

The 1990/1991 Arnold rapido catalog lists 43 locomotives with Factory-installed decoders.  This catalog also lists about 20 locomotives that can be converted to Arnold Digital by a qualified dealer. Given the general time frame, these digital locomotives would have 2 digit addresses between 01 and 80.  There were no other adjustments for the mobile decoders in that era.

In addition to the Arnold Digital items, several Märklin control devices could be used with the Arnold Digital N system. Here, a list of Arnold Digital items:

  • 86002 - 52 VA power supply
  • 86015 - Booster
  • 86028 - Central Unit N
  • 86030 - Programmer
  • 86035 - Control 80 locomotive controller
  • 86040 - Keyboard solenoid device controller
  • 86078 - Decoder k87 for solenoid devices

Also listed in the Arnold catalog were several related Märklin items:

  • 6038 - 180 cm ribbon cable for remote throttles and keyboards
  • 6039 - 60 cm ribbon cable for remote throttles and keyboards
  • 6041 - Switchboard for track diagrams
  • 6043 - Memory, for saving a series of solenoid commands
  • 6050 - Computer Interface
  • 6088 - s88 Decoder for track detection
  • 6089 - 200 cm ribbon cable for connecting s88’s

There also were several accessory items and an Arnold Digital book:

  • 0040 - Digital Handbook (German language)
  • 86050 - Diskette for Commodore computers
  • 86051 - Diskette for Atari computers
  • 86076 - Connection Module (for linking analog and digital segments of a large model railroad)
  • 86077 - Universal Relay

The Digital product line appeared in several Arnold catalogs in the 1990’s and then eventually disappeared as other, more modern DCC command control systems were introduced. The Arnold system has some limitations, notably in locomotive addressing since it could only handle locomotives 01 - 80, but it is a reliable system that still enjoys a following.

Next: Arnold Digital - Second Generation

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