The invention relates to a method of regulating the temperature of a heat regenerator used in an installation for storing energy by adiabatic compression of air. All of the wheel sets are vertically adjustable to negotiate stairways and similar changes of elevation. A coupling mechanism can be included and associated with the connector portion so as to provide the connector portion with substantially uniform contact across a contact surface area with the conducting member. If it does not so qualify, the customer’s original selection will be dispensed and the transaction ends.