NOVELTY - The installation (1) has a looping carriage riding on a pair of external rails (5), which enlarge or diminish strip loops to maintain constant strip speed in a processing section when an adjacent processing section runs for certain time at different speed. A strip supporting carriage (2) comprises a vertical frame placed on wheels (4). The frame is connected to inclined brackets (8) provided with guiding cam rollers (12) riding in guiding profiles or girders (9) located under the rails to guide the strip supporting carriage on the rails in an anti-tilting-over manner.    USE - Horizontal strip accumulator installation for use in a continuous strip processing line for a metal industry and a plastic or fabric production industry. Uses include but are not limited to a pickling line, continuous milling line, PLTCM line, continuous annealing line, galvanizing line, tin plating line, color coating line, anodizing line and a polishing line.    ADVANTAGE - The installation designs the strip support carriage, which diminishes a theoretical accumulator capacity by presence of the support carriage at a possible minimum. The installation reduces erection on a flat ground having a lowest strip strand without adverse effect and utilizes a passive hooking and unhooking system at specified locations so as to avoid non desired efforts in the rails. The installation reduces a space necessary for accommodating the strip supporting carriage and avoids a need of an extra drive or transmission system. The rails are attached onto open profiles so as to prevent effect on total accumulator height. The installation allows a simple unhooking, locking and hooking system to be completely mechanic and automatic without needing external power and to be lodged in a carriage center to avoid undesired efforts or moments in the system, thus using open U or similar profiles for a support carriage framework, and hence resulting in lighter strip supporting carriages.    DESCRIPTION OF DRAWING(S) - The drawing shows an elevational view of strip supporting carriages.    Horizontal strip accumulator installation (1)    Strip supporting carriage (2)    Wheels (4)    External rails (5)    Inclined brackets (8)    Guiding profiles or girders (9)    Guiding cam rollers (12)