Accurascale’s ‘OO’ gauge CDA

One of the late developments of the successful Merry-Go-Round (MGR) coal hopper wagon was the 124 CDAs built for china clay traffic in 1987. Accurascale releases the first bespoke ‘OO’ gauge model of the CDA as part of its MGR family of models.

MGR family survivor

A TOTAL of 124 CDA wagons were built at BREL Doncaster in 1987 and 1988 to replace ageing wooden-bodied OOV vacuumed braked china clay tipplers known as ‘Clayhoods’.

Whilst the passing of the ‘Clayhoods’ was mourned by enthusiasts, the longevity of the CDA wagons has given them a cult status of their own. They have outlived the MGR coal wagon by some time and continue to be used daily on the traffic they were constructed for, which is to convey china clay to the docks at Fowey from various Cornish clay dries.

The CDA has become very much part of the Cornish china clay landscape since introduction. Traction has evolved from the famous St Blazey Class 37/4 (374xx and 376xx) fleet through to present day Class 66s operated by EWS and latterly by DB Cargo.

The CDA wagon fleet is based at St Blazey, Cornwall, where maintenance and repairs are undertaken by current owner DB Cargo. St Blazey is the hub through which china clay traffic is concentrated and the CDA wagon rarely, if ever, wanders away from the area.

Prototype wagon

With English China Clays (ECC International) pushing for a replacement for the obsolete ‘Clayhood’ wagons in the 1980s, a little mentioned prototype wagon was converted in 1987 from MGR HAA No. 353224 to test the concept of a china clay MGR wagon. It was fitted with a flexible cover and roller bar similar to that fitted to tipper lorries to prevent dusting and to protect the load. It was TOPS coded as a CBA and not a CDA until construction of the new CDA wagon fleet was started.

CDA details

The 124 new-build wagons were numbered as Nos. 375000-123 and finished with ECC blue cradles and covers together with ECC International logos. The remainder of the wagon consisted of an unpainted hopper and black underframe in common with the rest of the MGR wagon fleet. A lining was applied to the interior of the wagons to help with discharge of the load after it was found that crosscontamination between clay types was becoming a problem due to residue sticking to the inside of the hopper.

A lining was applied to ease unloading which subsequently degraded, contaminating the clay which is required to be kept both clean and as pure as possible. The wagons were quickly withdrawn from traffic to have the lining removed using shot blasting, a task undertaken at a hastily established facility at St Dennis Junction.

The wagons serve the china clay industry well, passing into EWS ownership and subsequent repainting of the cradles maroon. Record pictures show various livery changes from

rebadging, loss of the ECC logos after ECC International was acquired by Imetal/Imerys. Patch painting and subsequently, rebadging with DB logos, the version currently offered on the new Accurascale model adds to their character.

CDA conversions

The fleet was strengthened with 14 converted HAA wagons in 1989. They were numbered in the same number sequence, as Nos. 375124-137. The reviewed models represent the as-built CDA wagons of 1987 and 1988.

Hopper and cradle

One of the things one can say about the brand-new CDA, it is a very sharp and crisp model. Another is the use of a flexible tooling system that allows a wide range of variations to be introduced in the MGR range of models which has been used to advantage in the new CDA model.

The hopper is bespoke to the CDA, including the drainage slots in one side of the wagon, a differing discharge door pattern and the necessary locating points for the external fittings, together with the flexible roller covers. The hopper frame is a fine moulding and delicately tooled too. This fits around the hopper sides and to the underframe very neatly and with no unsightly gaps.

CDA-specific cover

Accurascale was serious about producing a completely authentic model of the

CDA and this extends to the roller cover, its bar and operating equipment. Rather than use a convenient singlepiece moulding, the top consists of several distinct parts including the cover fastenings, the strapping on the roller bar and end equipment. It is supported by the equipment box covers on the wagon ends, all of which are of the correct style and position on the model – applied as if they do belong there.

Underframe and brakes

The same level of fine detail is applied to the CDA underframe as the early version of the MGR wagon reviewed in REM 219. A cast metal underframe provides the weight, to which plastic mouldings for the axleguards, door stop bangers and the brake equipment are applied. Brake equipment is also the same as the HAA with clasp brakes on diagonal wheels and discs on the opposing wheels.

Noteworthy is the neatly modelled taper to the underframe together with the deep headstocks. Several differences exist compared to the original HOP32 model and that is the fitting of the brake distributor, located on one end of the underframe with its protective cover and the modelling of the correct buffer type which differs from those fitted to HAAs.

Couplings, wheels and the ride

Couplings, NEM pockets and wheel sets are the same as those fitted to the HAA model except the brake disc inserts which are modelled differently on the CDA. The wheels turn in brass pin point bearings making the wagons very free-rolling. A long rake associated with today’s operations will not challenge a Hornby Class 60 or Hatton’s Class 66 in the slightest. Of course, the CDA could be observed being worked in shorter rakes when concentrating loads on St Blazey Yard, particularly in BR Railfreight days, hauled by Class 37s.

Testing demonstrated both the smooth, free-rolling ride and the ability of the models to negotiate proprietary track without difficulty. All four wheels of the wagons in the sample box sat square on level track and the wheels themselves were not fouled by the brake shoes which are closely aligned with the wheel tyres.

Livery application

Contributing to the sharp appearance of the Accurascale CDA wagons is a crisp livery finish enhanced with paint patches on the hoppers and rebadging with DB logos over EWS markings (DB Pack 1). Patching effects are applied to wagons in the other packs too. The ECC International version in as-built condition remains to be represented in the range. Livery finish is pristine even though the real wagons became grimed from china clay dust and residue very quickly.

Overall impressions

The quality of finishing and assembly is beyond reproach adding up to another five-star model from Accurascale, supplied in its usual hard box with detailing parts and information. As has been mentioned in the past, the cost per wagon at £25 is remarkable value for money and is even better when two or more wagon packs are ordered at the same time when a discount is applied. If only such accurately modelled CDAs were available in ‘N’ gauge.

Produced by Accurascale www.accurascale.co.uk

£ RRP £74.95

Accurascale’s CDA has been welcomed by the china clay traffic modelling community. They are the first bespoke ‘OO’ gauge models of the MGR type china clay wagon which dates from 1987 to present day.

 As claimed by Accurascale, there is a sharpness to the MGR wagon models which is rare in ‘OO’ gauge, and this has been carried through to the CDA model.

↑ No. 375002 and No. 375091 are two DB examples from Pack 1 which brings the wagons completely up-to-date in model form. Original ECC International branded versions remain to be released.

1 1: No. 375002 with maroon cradle and DB logos applied over EWS ones.

2 2: No. 375030 with patch painting of the cradle alongside a maroon roller cover and DB logos.

3 3: No. 375091 has a maroon cradle and DB patch applied over the EWS legend. The St Blazey lizard logo is a nice touch.

 It is not a one-size-fits-all model but is made up of specific tooling for various components including the hopper assembly, brake equipment and even the buffers are of the correct type.

↑ Livery and assembly of the model is as good as one could wish for. The CDA is of exceptional value given the large number of parts fitted to it. It is a fivestar model based on this combination of presentation, detail and finish for the price.

 Several pieces and small fittings make up the roller cover, its bar and mechanism. The strapping on one side of the top is modelled with etched metal giving it a particularly fine appearance.