NSWGR 75' TURNTABLE KIT

$650 per kit

PLEASE NOTE: 1st run pre orders have now been filled.

All new pre orders for kits to be available March 2023 

Prototype Info.

The first 75' turntables in NSW appear to have been those installed at Enfield locomotive depot in 1916. Three sheds at Enfield were fitted with manually operated 75' turntables to enable them to turn larger locos in years to come. At around 1923 and after the reclassification from the NN2 Class to the 36 class, the 36 could not be balanced on the more common

60' turntables of the time and could only be turned on these tables by separating the tender from the loco. To accommodate the larger loco, 75' Turntables were installed at the appropriate depots from 1922 on.

When the 4-6-2 38 class loco entered service in 1943 its wheelbase of 65'6"enabled it to be turned on a 75' turntable manually without any difficulty.

The standard NSWR 75' turntable was of a single span type. It was fabricated from steel and was either electrically powered or manually operated, depending on how busy the location was. The only NSWSR locos that could not be turned were the D57 and 58 class and the AD60 Beyer Garratts.

Information at hand shows there were a total of twenty 75' turntables on the NSWGR system.

Kit Details.

 This has been a personal project of mine for nearly 10 years. The desire to have a highly detailed, accurate and most importantly, perfect working turntable was desired. The kit is primarily based on the manually operated 75' turntable at Muswellbrook, what I hope to have as the feature of my HO home layout, however most of them followed the same design.

Unlike other turntables on the market, the pit itself includes all the details of the prototype like concrete part lines, correct profile and drainage details. 

The pit is made from an aluminum billet that was hand machined to the correct profile and to ensure absolute accuracy. It incorporates a stepped edge that accurately aligns the ring rail that comes pre rolled in the kit. A central hole houses a flanged bearing that accepts the main shaft ensuring that its perfectly centered in the pit. The pit has all the part line and drain grate details. The master pattern was used to reproduce cast Hydrocal (high quality casting plaster) pits that are cast directly onto marine grade 12mm plywood. The plaster allows easy staining or painting to better represent concrete. Scale timber is provided to replicate the timber blocks that support the ring rail along with the timber sleepers that formed part of the pit wall.

 

The bridge is constructed from a nickel silver etch. Again, it has all the necessary rivet and brace details as per the prototype. The four outriggers on the bridge incorporate small ball bearings that run around the ring rail which take the weight of any loco up to and including the 38 class, giving ultra-smooth operating characteristics. There are cast brass handrails along each side of the bridge along with 3D printed details for the lock pawl, at the ends of the bridge, and lock plates for the takeoff roads (8 supplied in the kit). The completed bridge locates over an accurately sized 3D printed block attached to the main shaft. This block has a two-pin female connector fitted inside it and the bridge itself has a small PCB with male plug to bring power to the bridge rails. The bridge can simply be located over the block and plugged in for electrical supply. It can also be removed for cleaning and servicing. 

On the underside, a simple wiper system is used for bringing track power to the bridge so your sound equipped locos can turn a full 360 degrees with no interruption to the sound. Everything is included in the kit less rail for the bridgethe indexing system and the usual paint, glue solder etc.

Our turntable has been designed for use with a number of commercially available indexing systems that use stepper motors for the drive.

INDEXING - The most important part!

Included with the kit is an acrylic disk that is mounted on the underside of the turntable. This disk is laser cut to accept our three primary recommended motor drive options for turning and aligning the bridge to the roads.

These motor drives, primarily stepper motors, attach directly to the main shaft via the included rigid coupling eliminating any possible backlash from gears or the like ensuring ultimate accuracy for indexing alignment. 

My primary recommendation for indexing is the NYRS (New York Railway Systems) indexing system from the USA. This system features a keypad control, indexing of up to 99 tracks, Indexes both ends of the bridge, very fine 0.025 degree indexing resolution. Simple programming, select from 14,400 possible stopping locations, high torque stepper motor with internal gearing for quiet slow smooth operation.

 

Alternatively, a slightly cheaper option with similar features is the MERG (Model Electronics Railway Group) indexing kit from the UK. This is however a kit, and the electronics board would need to be assembled. Again, it uses a stepper motor with separate gearbox but has a much simpler control via rotary switch and toggles. It can only program a total of 32 tracks with a possibly upgrade to 64 track stopping positions. It has the momentum for bridge speed and seems to work OK.

We are in the process of having a PCB made for the MERG kit that eliminates the issues caused from bad connections to the hexadecimal rotary switch. This board along with an assembly service for the kits is being considered. Please contact us for more info.

 

The final option is for those who want just a single 180 degree turn system. We have been offered to use a simple 3D printed gearbox drive unit that allows an adjustable 180 degree turn of the bridge. This gearbox was designed by fellow modeller Stephen Buck.

The simplest variation uses cheap Ebay gearmotors and gears fitted inside the gearbox along with two micro switches, diodes and a toggle switch that starts and stops the bridge. There is also an option have the gearbox driven by a stepper motor that can be controlled via Audino. This is still under development but is looking very promising and initial testing shows it to be a good simple drive system.

All three of the above systems are adaptable to our kit. Links to both the NYRS and MERG systems are below.

Video links are provided to show the three systems in use on our test setup.

You can of course source your own indexing system. There are many other systems available including those that use Arduino control. 

 

 

          

  

       

Musselbrook Roundhouse 18_edited.jpg
75' Turntable Components.jpg
Alloy pit master.jpg
Etch Sheet_edited.jpg
Deck Block Removable bridge.jpg
75'Turntable Pit casting.jpg
310738085_1346434072556013_8281939550545710496_n.jpg
Drain Grate Details.jpg
NYRS Drive unit.jpg
Stephen Buck 180 drive.jpg
NYRS Keypad_edited.jpg
Stephen Buck 180 Drive 2.jpg

Below are video links of all three of the indexing systems running on our sample Turntable.