Aspen’s ES-Series (Equipment Series) are equipment/machinery hauling trailers which primarily serve the construction industry. Payloads of these trailers are 85 tons, with axle configurations of 10 through 13 axles (including truck axles). Aspen ES-Series trailers feature mechanical removable necks with a tower jeep or hydraulic removable necks with double drop, square tail frames. ES-Series trailers can be configured with a variety of components including various deck widths and lengths including custom options. The ES-Series trailers have common air/regulated air suspensions or walking beam (trunnion) suspensions with transporter equalization achieved by a mechanical equalizing inner frame “Cali-Legal” or “West Coast” design. Aspen’s ES-Series of trailers are available in specific regional configurations (Interstate – US and Canada, US North West and California) to maximize trailer configurations for specific regional regulations.