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Image: Hornby


Hornby Railways R2420

Review and DCC decoder installation by Doug Teggin

Prototype info

Built: 1958 - 1962 by Brush Traction at Loughborough; Dimensions: 17.3m x 2.67m x 3.87m; Weight: 106.7t - 111t; Wheel Diameter: 1092/1003mm; Design/Maximum Speed: 90mph/60mph.
Source: Hornby

The AIA-AIA Diesel Electric Class 31 was one of the Pilot Scheme locomotives ordered by British Railways to replace steam traction. They were originally built with Mirrlees JVSS12 1250bhp and 1365bhp engines, but these were not successful and in 1964 a programme of works commenced to re-engine the fleet with 1470bhp English Electric engines and Brush electrical equipment. The locomotives were originally known as class 30 under TOPS, with re-engines examples joining Class 31. The class was originally intended for service on the Eastern Region, but gradually became common in both the Western and London Midland regions too.

Several sub-classes of Class 31 exist:

  • 31/0 - First bitch of locos, fitted with electro-magnetic control equipment - withdrawn early as non-standard
  • 31/1 - The standard locomotive
  • 31/4 - Fitted with ETH apparatus
  • 31/5 - Former 31/4 with the ETH isolated for Civil Engineers Department use

Source: Wikipedia

BR Class 31, no. 31018, at the National Railway Museum in York, on 3rd June 2004.
Photo: Phil Scott

Class 31 Trivia: BBC Top Gear level crossing collision

On the 21 August 2006 Network Rail and the BBC television programme Top Gear staged and filmed a crash between a Class 31 railway locomotive and a family car in order to promote rail safety. The off-limits event was the first of its type for 10 years and took place at Hibaldstow level crossing near Scawby in Lincolnshire where the B1206 road crosses the Barnetby–Gainsborough railway line.

Two Class 31 locomotives and a parked Renault Espace were used during the crash. Network Rail's own 31233 was used to propel 31107 up to a speed of 80mph. Whilst the rear locomotive slowed down to a stop, 31107 continued to coast at a speed of 70–80 miles per hour into the road vehicle parked across the eastbound 'up' line.

For the crash, locomotive 31107 received a special black livery with the slogan "Level crossings — Don't run the risk" along the side in white lettering. The final 5 minute segment, presented by Jeremy Clarkson, was originally scheduled for 4 February 2007 but was rescheduled, apparently due to a fatal crossing crash at Dingwall two days earlier.[1][2] It was eventually aired on BBC Two on 25 February 2007, shortly after the Cumbria derailment. A repeat of the program was pulled following a further level-crossing accident.


Model info

Length: 225mm; Running number: D5512; Livery: BR green; Period: 1959; Features: Twin bogie drive, pick-ups on all wheels, NEM couplings, DCC ready; Finish: Pristine; Motor: Five pole skew wound. Source: Hornby

Click on the photos of the model for a larger view.

This Hornby Model has all the features of a modern Hornby loco: DCC ready, directional lights, strong motor, flywheels and quality gearing. This locomotive has head-code discs and BR green livery with white stripes and late type crest worn from 1958 to the mid 1970's.

The model has a good feel to it. Substantial and strong. Immediately you see the 6-axel drive and all wheel pickup. This model will have good traction and not get caught up on tricky sections of track.

It is a good looking model, fitting in with my scheme of late steam and early diesel, it will run around along with the Class 20s happily without causing too much of a fuss amongst the steam engines.

There is plenty of detail on the visual front, but not too many bits and bobs that would be prone to falling off. The cab doors open to reveal a semi-detailed cab, but you don't get to see much trough them and it is better to remove the body to add a driver if that is your intention.

A detail pack is included with indicator disks, brake and heating hoses and an extra tension lock coupling.

The roof fan is connected to the front flywheel by a belt-drive and turns accordingly. A large PCB includes a rectifier and smoothing circuit to operate the lights under DC power. A 12-pin blanking plug is supplied allowing easy fitting of the DCC decoder.

I have opted for the Lenz Gold decoder for this model as it deserves a good decoder with Back EMF to ensure smooth running. Full speed control is also a requirement on this loco and it was not extremely fast in it's day.

There is not much space above the PCB and the space under the rectifier diodes may be fine for a Hornby decoder, but not for the Lenz. The Lenz Gold fits nicely underneath the PCB (removed with two screws) and is held in place with double-sided tape and perhaps a little masking tape for security. You don't want it to come off and foul the drive shaft underneath.

Test the loco with the body off on a DCC programming track. First off, read the factory default CV1 address to see if the installation is fine. Set the long address and then on a test track, check basic running and the lights.

When all is fine, replace body by fitting the cab ends that hold the LED lights to the body. Hold each cab in the body with forefinger and thumb of each hand at each end and gently lower the body onto chassis. I found that if you fit the cabs to the chassis first, the protruding lights prevent the body from being fitted. If you do it slowly, it goes on easily without fuss.

DCC CV Settings for Class 31 'D5512' Locomotive
Adr 5512 Long loco address
CV1 3 Default Address
CV2 0 Minimum Speed (V Min at step 1)
CV3 6 Acceleration delay (0-255)
CV4 6 Brake Delay (0-255)
CV5 120 Max speed (V high)
CV6 60 Speed curve shape (V mid)
CV29 34 Decoder Configuration
CV29 is set to 34 [decimal values in brackets] to allow  28 or 128 speed steps [2] and to use the extended long address [32].

The rest of the CV's are left untouched (factory default).



The model runs very smoothly. So smoothly that after being spoiled with the Bachmann Class 20 loco with sound, I wish that this Class 31 made some noise.

The lights look good. Perhaps that could be slightly weathered to tone-down the pristine look.

The detail of the body is fine, the bogies are well detailed too. The rotating fan is interesting, but is hardly noticeable when the loco is moving. How could we simulate black smoke coming out...?

The RRP of the model is £95.00. It seems that a year on, there are still quite a few in circulation. The shops that still have it, sell it for between £67.50 and £85.00. This particular model was purchased for just over £30 at a swapmeet. So if you can find it cheaply, you could possible get a great loco for a good price.

- May 2007



All text, photos & graphics, unless otherwise indicated ©2007 Doug Teggin - All rights reserved.

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