7 set A4 Project.

Notes on HORNBY DUBLO 3 rail OO or 00 gauge components.

1. Some Technical Notes on the mechanism:

David Neale in Canberra, Australia, who is well known as an authority on the Hornby Dublo model range introduced in 1938 says:

The Dublo A4 was one of the best model locos to be produced before the war. The Dublo A4 was also very revolutionary in 1938, as it introduced 12v DC, the first production model loco to have this standard. (Most models of the time ran on 20V AC). This was taken up post-war by other manufacturers, and has thus become the standard voltage of today's model train market. Meccano and Marklin were very similar model train manufactures having the same ideals in quality.

Dublo were certainly quality models for their time, and produced under that brand, until 1964. The locomotive was powered by a 12 volt DC open-framed miniature electric motor. David Neale of Canberra, Australia, makes these comments on the motor.

The mechanism in the Dublo A4 was superbly designed in 1938, and beat all other manufactures in their day. The two engineers at Meccano responsibile for the 1938 Dublo design were Donald Smith (general design) and Ronald Wyborn (electrical design). Both men were of a previous era where British was best, and perfection was paramount.

I did correspond with Ron before he died and he was certainly a perfectionist in my view. His detailed letters on Dublo motor design and magnetiser specifications were quite something. Ron stated from the outset he wanted the Dublo motors to have pin point shafts with adjustable thrust ball bearings.

Dublo motors went through 3 stages of development, first the 3/4 inch standard type as in the A4, the 1/2" in the first Castles and finally the 3/4" Ring-Fields. All 3 of these motor designs had thrust ball bearings. Not even Marklin had this design quality and only the Swiss manufacture Hag do today, a testament to Dublo's quality.

Dublo loco mechs were also the first with radio suppression units in 1950. Meccano actually defined these British standards to the government of the day as they were also the leaders in this area.

2. Comparisons

Mr Paul Stolk from the Netherlands has kindly supplied me with a comparison picture of 3 models, with the Hornby Dublo Silver King model from 1951 in the middle. The upper model is the Hornby R2684 A4 Mallard 70th anniversary gold plated edition (released in 2008), and the bottom model is a Marklin HO scale 3097 (1:87) 03 class express engine from the 1980s.

Maerklin 3097 03 class Pacific in H0 scale versus Hornby Dublo A4 Silver King in 00 scale and Hornby 2-rail A4 Mallard in 00 scale.
I have alligned the buffers of the 3 loco's at the front end.
The Maerklin 03 has length over buffers of 27.7 cm.
The Hornby Dublo has length over buffers of 28.3 cm,height to chimneytop is 5.2 cm.
The Hornby Mallard has length over buffers of 29 cm,height to chimneytop is 5.6 cm.

7 set LNER A4 models

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