During mid-2014, UKRL were reportedly considering upgrading a Class 56 with new engines and electronics; the proposed arrangement involved two 1,900 hp engines for a combined output of 3,800 hp. However, this was emphasised to be "blue sky thinking" and not likely to happen soon. Further information was published two years later. By then, three different options were being considered; these were: two main engines, a single main engine, or a single main engine plus an auxiliary engine. It is expected that a re-engined Class 56 would cost around £1.8 million, compared to £3 million for a new locomotive.