Trolleys are used for cranless assembly, disassembly and transport of downhole tools or other cylindric parts. For different tool diameters, the distance between the support rollers is adjustable and for different tool lengths, the center bar is stepless extendable. To allow working in an ergonomic position, the height of the trolley can be adjusted. Each trolley is grounded and can be used in ESD (electrostatic discharge) environments out of the box. A turnable tray for tooling equipment is optional available.