42693 "Stumbles" Tandem Roller

General History of Type

Up to and including the 19th century, roads were usually made of crushed, graded and rolled stone. Thus, the typical steam roller was heavy, slow and robust. However, with the advent of new road making materials, lighter, quicker reversing and manageable rollers were required, especially in the smaller sizes for rolling paths and drives.

 

....as manufactured by Robeys

As the Robey steam wagon was in full production with the famous pistol boiler which had no stays, it was an ingenious step to take a standard wagon boiler & engine unit, fit it with rolls and market it as a quick reversing roller. Altogether, 79 Tandems were built, the first being 39440 in January 1922; the last, which is in preservation, was 48869, built in March 1939. Of the 79, 22 were sold abroad.

The rollers adaptability and simplicity renders it especially suitable for all modern forms of road construction such as tar macadam, asphalt and bituminous carpeting, and for all gravel and metal roads.

 

This engine Engine Book entry

Number

Machinery

MO

Delivery

Name

42693

8 ton tandem roller

31461

24.9.1925

Devon County Council

 

Description

Steam rollers were commonly of the traditional 3-roller design. The Tandem roller, as the name suggests, has only two rolls. Furthermore, traditional rollers were gear-driven, like traction engines: the Tandem is chain-driven via a Renold 2" pitch roller chain. There are other notable features, distancing this design from what had gone before, eg. instead of a bobbin-and-chain steering system, a worm-and-quadrant was used. Finally, unlike other rollers, traction engines, etc., where the boiler is the 'chassis', the Tandem rollers boiler sits in a separate rolled-channel girder chassis, thus relieving the boiler of many working strains. All controls are placed so that one man can drive and steer. The main design feature is the loco-type boiler with round firebox and no stays with a working pressure of 200 lbs. sq. in. (in the wagons it was 250 lbs sq in) tested to 425 lbs sq in. Fitted with double Ramsbottom safety valves, Klinger reflex water gauge, compound engine, crankshaft of forged nickel chrome vanadium steel heat treated to 70 tons per sq in with balance weights forged solid with crank. Ball and roller bearings.

 

Dimensions

Compound cylinders: (hp) 4.25" dia. (lp) 7.25" dia x 7" stroke.

 

Known history in its working life

Bought by Devon County Council in 1925 and delivered to Bow railway station on a LNER well wagon.

 

History in Preservation

1962, parked up in 'The Meadows' children's playground. Over the next 20 years most removable fittings disappeared, some reputedly ending up in the canal. By 1982 corrosion was extensive, and through hole in the boiler lagging, asbestos was discovered. The Robey Trust was formed to restore its roller as a part of the history of Tavistock .

 

Restoration

Took 11 years. A new boiler was built by Robeys, the last before the works closed down in 1988.

 

Known others in existence

40668 5 ton Australia

43159 8 ton Sydney, Australia

40672 7 ton FE5391 Frithville, Lincs

{43747 8 ton VK4540 Durham} (dismantled for conversion)

41593 8 ton FE6255 Northumberland

44083 7 ton VL2370 Kent {Tri-Tandem}

41602 7 ton FE6319

45655 7 ton VL2773 Robey Trust {Tri-Tandem}

42129 8 ton RL75 Truro

46935 6 ton CZ2432 Humberside

{42287 7 ton FE7632 Lincs} (converted to wagon)

48869 8 ton EDV946 Oxfordshire

42520 ? ton FE7632 Bressinham

42693 8 ton FE1490 RobeyTrust

Total (still in existence) 10 Tandems, 2 Tri-Tandems

 

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