A Short History Of Tri-ang and Hornby Turntables...

[Ruffnut Thorston]

A Short History Of Tri-ang Hornby Turntables.

 

The first Tri-ang Turntable was announced in 1955, though it did not appear until 1957.

 

This was the R.45, and was made to fit the "Standard" track (That is the Grey track with "Ballast" built in. Black "Series 3" track also fitted, as this was basically the same, but with the "ballast" removed.) This was electric operation only, and was made largely of metal.

 

 

 

The "bridge deck" was mounted on a metal circle (a bit like a biscuit tin lid!). There was only two tracks, and the 'table was only suitable for turning locos. The operation was by push button.This remained available until 1962, when Super 4 track was introduced.

 

http://www.tri-ang.co.uk/oonew/TurnT.htm

 

The next Turntable, announced in 1963 (Available Summer.) was the R.407 (Hand operated) and R.408 (Electric). (The motorising kit was X.319).(After 1965, only the electric version was available.)

 

 

http://www.triang.co.uk/oonew/TurnTNewHand.htm

 

http://www.tri-ang.co.uk/oonew/TurnTNew.htm

 

 

This was a great improvement on the R.45.

This new turntable could feed 3 sidings, and was mostly moulded plastic.

 

This turntable was re-numbered R.408U on the introduction of "System 6" track. The turntable had Super 4 Track, and used the R.476 "Converter Track" to connect to System 6 layouts. The "U" suffix was dropped in 1973, and production ceased in 1974.

 

 

 

I do think there may have been a last batch of the R.408 Turntable that had code 100 rails on the bridge and outlets. Possibly in 1973, when the “U” suffix was dropped?

 

Similar to the old Gravity Unloading bridge that did get retooled and fitted with code 100 rails, after being supplied with Super 4 rails, and two Converter Tracks.

 

The R.408U also came with four ramps that clipped into the base, to take the converter tracks down to baseboard level.

 

The ramps, dummy lights and fencing supplied with the R.408U entailed a minor retooling to provide the mounting points.

 

At the same time, the bridge parts, the control box operating buttons, and other previously Maroon plastic parts, including the drive gear, were made in a black colour.

 

It is, in my opinion, far superior to the Geneva Gear drive later turntable.

 

One weakness seems to be the actual drive gear, which can go fragile and break apart, especially if the fixing screw is over tightened.

 

Contamination with the wrong type of oil probably doesn’t help either.

 

The maroon gears seem to be more prone to this.

 

Unlike the Geneva Gear drive of the later Hornby Turntables, the R.408 rotates smoothly between dwell points.

The inlet and outlet rails are in fact castings, and incorporate a pin that carries current to the contacts below the base.

 

The drive on the R.408 is ingenious, and uses a lot of standard parts.

The motor is the OO Gauge version (X.05) of the TT XT.60 motor, the same as fitted to the Lord of The Isles and Caledonian 123 locos.

The intermediate gears are the same as on the driving axle of most steam locos, 40 teeth brass. Later 40 teeth Plastic gears when they started being used on the locos.

 

The shaped drive gear (pinion) causes a dwell at the outlets, to give you a chance to stop the turntable in alignment.

 

The Part Number for the pinion is not listed in the instruction leaflets I have, and there is not a service sheet listed in my indexes.

 

There is also a tension spring, ST.6053, that holds the motor assembly in position.

 

Hopefully the attached images will help....Note that the pinion has "A" on it, and is held on by a screw....

 

 

 

 

Also see here...Includes a list of part numbers for the conversion kit...saves me typing them out!

 

http://www.triang.co.uk/oonew/TurnTConvert.htm

 

Hornby Forum user Plumloco2 has had new replacement drive gears (pinions) 3D printed in Nylon.

 

They have made it as stong as possible by not having the cutaway in the centre.

 

If anybody wants one they are on Shapeways website. 
 

https://www.shapeways.com/product/89WXTW2S5/triang-railways-r408-turntable-drive-pinion?optionId=74049969&li=marketplace

 

Link tested and working ok...

 

 

The Hornby Railways Turntable was planned in 1975, and arrived in 1977. (Made until 1981) This was R.410, and was supplied "hand operated".

 

This worked by rotating an unusually placed water crane.

 

It used a Geneva Drive system, in which a large gear wheel has a raised section that engages in tracks on the underside of the outer ring of the turntable, dragging it around in a series of jerks.

 

This causes the Bridge section to pause at every outlet, and at the same distance between outlets, to give you a chance to turn off the motor, or stop winding the water crane handle.

 

A motorising kit (R.411) was available (1977-1990) to convert the Turntable to electric operation.This version of the Turntable had up to seven outlet tracks. Each clipped into position.

 

This was replaced by the R.414, which was basically the same, and hand operated (The same motorising kit fitted.), but had provision for up to thirteen outlet tracks. (only 8 were included!) This was made from 1982 until 1993.

 

From 1994, the R.070 turntable was available. This was electric, and basically the R.414, with the Motorising Kit already fitted.

 

 

 

 

(Information from Pat Hammond's "Rovex" books...the internet, and items in our collection )

 

Edited February 20, 2021 by Ruffnut Thorston
More added tidying

[Dagworth]

5 minutes ago, Ruffnut Thorston said:

The shaped drive gear (pinion) causes a dwell at the outlets, to give you a chance to stop the turntable in alignment.

 Properly called a “Geneva drive” 

 

https://en.m.wikipedia.org/wiki/Geneva_drive

 

Andi

 

[Ruffnut Thorston]

The Geneva drive is used by the Mk3, Hornby turntable.

 

The R.408 uses a drive gear with offset teeth that engage at the outlets, causing the drive gear itself to disengage for a short period  while the motor is still able to run. Then the offset teeth disengage and the bridge starts to rotate again.

 

It is difficult to describe, but it isn’t the Geneva pin in a slot system, which produces a jerky movement. 

[Dagworth]

The R410 that I had when I was young was definitely a Geneva drive pin that engaged in slots under the bridge deck and a D shaped segment on top of the large gear. 
 

see 

 

 

Andi

 

 

[Ruffnut Thorston]

Yes, your turntable is the last type, introduced by Hornby Railways in 1977.

 

These are indeed Geneva drive.

 

The R.408 is a different model entirely, and uses a completely different drive system...

 

 

See here...

 

http://www.tri-ang.co.uk/oonew/TurnTConvertAA.htm

 

 

Edited February 13, 2021 by Ruffnut Thorston
Link added

[sandwich station]

When I lived in the UK about 20 years ago, there was a trader called Dave Wills (from East Kent) that dealt in second hand railways, he had some of those gears cast out of white metal.

[Silverfox17]

The 408 version was also made with a smaller base and deck for TT gauge. It used the same motorising system as the 00 one and also had cast outlet rails. It too was sold as manual or electric with an optional motorising kit. 

 

Garry 

[TT3]

Just a quick follow on from silverfox, the tt version was defiantly a scaled down 408 complete with a x03 motorising kit.

Edited February 14, 2021 by TT3

[TT3]