Abstract The number of compressors installed in each compressor station of a pipeline system, as well as their arrangement, has a significant impact on the availability, fuel consumption and capacity of the system. This paper discusses the impact of the type and arrangement of turbomachinery equipment used in compressor stations. Introduction The economic success of a gas compression operation depends to a significant extent on the operation of the compressors involved. Important criteria include first cost, operating cost (especially fuel cost), life cycle cost, and emissions. Decisions about the layout of compressor stations (Figure 1) such as the number of units, standby requirements, type of driver, and type of compressors have an impact on cost, fuel consumption, operational flexibility, emissions, as well as availability of the station. Capital Cost: First Cost and Installation Cost Capital cost for a project consists of first cost and installation cost. First cost not only includes the cost for the driver and compressor, and their skid or foundation, but also the necessary systems that are required for operating them, including filters, coolers, instruments, and valves, and, if reciprocating compressors are used, pulsation bottles. Although not intuitively obvious, this is also the area that is affected by driver derates due to site ambient temperature and site elevation: The power demand of the compressor has to be met at site conditions, not at ISO or NEMA conditions.