The Class 3000 (C3K class) is a class of diesel multiple unit in service with NI Railways.
At the beginning of the 21st century, the majority of rail services in Northern Ireland continued to be operated using Class 80 DEMUs, which had been in service since the mid-1970s, and were becoming increasingly harder to maintain. NIR had not procured new rolling stock since 1994, when, in conjunction with Iarnród Éireann, it purchased locomotives and coaches for the Enterprise service.
As part of a major investment programme in the railways in Northern Ireland, NIR placed an order totalling £80 million, the largest single investment in rolling stock ever made by NIR, with CAF for twenty-three 3-car DMUs in 2002.
The new trains entered service in 2005 and 2006, gradually replacing most of the existing Class 80 units on the network (the main exception being services between Belfast and Larne, which were still provided by the Class 450 DMUs). The trains are capable of speeds of up to 145 km/h (90 mph), seat 201 (including 15 on tip-up seats) and have standing room for 280 passengers crush laden. The sets are numbered 3001-3023. All vehicles are powered. The individual cars are 3301 to 3323, 3501 to 3523 and 3401 to 3423. The end vehicles on each unit have cabs. 3001 is formed 3301-3501-3401 up to 3023 being formed 3323-3523-3423.
A cleanroom or clean room is an environment, typically used in manufacturing, including of pharmaceutical products or scientific research, with a low level of environmental pollutants such as dust, airborne microbes, aerosol particles, and chemical vapors. More accurately, a cleanroom has a controlled level of contamination that is specified by the number of particles per cubic meter at a specified particle size. To give perspective, the ambient air outside in a typical urban environment contains 35,000,000 particles per cubic meter in the size range 0.5 μm and larger in diameter, corresponding to an ISO 9 cleanroom, while an ISO 1 cleanroom allows no particles in that size range and only 12 particles per cubic meter of 0.3 μm and smaller.
The modern cleanroom was invented by American physicist Willis Whitfield. An employee of the Sandia National Laboratories, Whitfield created the initial plans for the cleanroom in 1960. Prior to Whitfield's invention, earlier cleanrooms often had problems with particles and unpredictable airflows. Whitfield designed his cleanroom with a constant, highly filtered air flow to flush out impurities. Within a few years of its invention in the 1960s, Whitfield's modern cleanroom had generated more than $50 billion in sales worldwide.