Robo 010001DE TT - SM42 843 Diesel Locomotive, PKP, Katowice Rolling Stock Depot, Era V, DCC with sound

Model of the SM42-843 diesel locomotive in Polish State Railways livery

Digital model of the legendary Polish SM42 diesel locomotive, known among railwaymen as „Stonka". Made in TT scale (1:120) by the Polish company ROBO — it is the manufacturer's first model in this scale. It reproduces a specific prototype — SM42 843 from the Katowice Rolling Stock Depot (Zakład Taboru) — in PKP livery characteristic of Epoch V.

The model is factory-painted and ready to run. It has a factory-fitted digital sound decoder, so it reproduces the locomotive's working sound effects and allows full control under the DCC digital system. It is fitted with directional white/red front lighting, realised with bi-colour LEDs (white and red) and changing with the direction of travel, as well as an illuminated driver's cab.

Model specifications:

• Scale: TT (1:120)
• Catalogue number: 010001DE
• Manufacturer: ROBO
• Locomotive: SM42 843 (Katowice Rolling Stock Depot)
• Model length: approx. 119 mm
• Epoch: V (1990–2006)
• Operator: PKP
• Power supply: DC current
• Control: digital (DCC)
• Decoder: factory-fitted digital sound decoder
• Directional white/red front lighting changing with the direction of travel (bi-colour LEDs)
• Illuminated driver's cab
• Factory-painted and ready to run
• Recommended age: 14 years and over

Note: a DCC digital command station and a powered track are required to operate the model.

The model is not a starter set and does not include track or a controller. To use all the digital functions — sound and independent control of the lights — a DCC command station (any controller compatible with the DCC protocol) connected to a powered track is required. The model can also be run on a classic analogue layout powered with DC current, but only provided that the decoder has the alternative power source function (analogue running) enabled — in the DCC standard this is governed by bit 2 of register CV29. This function is usually active by default, but if it has previously been switched off, supplying the track with DC current may damage the decoder. In analogue mode only basic running is available — without sound or digital functions.

Model railways – digital or analogue control?

In an analogue system all vehicles on a given circuit are controlled at the same time by varying the voltage in the rails — the higher the voltage, the faster they run. A digital DCC system, by contrast, allows several locomotives on the same track to be controlled independently at a constant voltage, and lets the lights and sound effects of each vehicle be operated separately. Model 010001DE has a factory-fitted DCC sound decoder and is intended primarily for digital control.

About the SM42 locomotive:

The SM42 (factory type 6D) was the first Polish series-built mainline diesel locomotive of its kind. Its technical documentation was prepared in the early 1960s at the Rail Vehicle Research and Development Centre in Poznań, and production was entrusted to the Fablok works in Chrzanów. The prototype left the factory in 1964 and series production continued until 1992 — 1157 locomotives were delivered to PKP, making the SM42 one of the most numerous and popular Polish diesel locomotives.

It is a single-cab, four-axle locomotive with a Bo'Bo' wheel arrangement and electric transmission. It is powered by an eight-cylinder a8C22 diesel engine rated at 800 hp (590 kW), built by the Cegielski works in Poznań, with a top speed of 90 km/h. It was designed for shunting duties and for hauling light mainline trains, both freight and passenger. Its distinctive features are the off-centre driver's cab and the large headlights.

Among railwaymen the SM42 earned the nickname „Stonka" (the Colorado beetle). It proved to be a very successful and reliable design — many units remain in service to this day, including modernised variants (such as the 6Dg type with a Caterpillar engine). The unit reproduced by the model — SM42 843 — was allocated to the Katowice Rolling Stock Depot (Zakład Taboru); the model depicts it in PKP livery of Epoch V, in the condition corresponding to its overhaul of 30 June 1998.

Prototype specifications (SM42, type 6D):

• Manufacturer: Fablok, Chrzanów
• Factory designation: 6D (industrial: Ls800)
• Years of production: 1964–1992 (1157 units delivered to PKP)
• Wheel arrangement: Bo'Bo' (4 powered axles)
• Diesel engine: a8C22 — 8-cylinder, 800 hp (590 kW)
• Transmission: electric
• Length over buffers: 14,240 mm
• Service weight: approx. 74 t
• Top speed: 90 km/h
• Brake: Oerlikon
• Intended use: shunting and hauling light mainline trains

About the manufacturer – ROBO:

ROBO is a Polish model railway manufacturer specialising in the rolling stock of Polish State Railways (PKP). The brand has earned recognition for its models of Polish electric multiple units — including the EN57 and EN71 — and PKP wagons in H0 scale. The SM42 in TT scale (1:120) is ROBO's first project in this scale, opening a new product line. ROBO models are aimed at collectors and enthusiasts of Polish railways, with an emphasis on faithfully reproducing domestic rolling stock and the liveries of specific prototype units.