in financial terms, in part due to the InterCity 225's prospective compatibility with WCML traction, reducing its development costs. A further cost-saving measure was the decision to base the InterCity 225's technologies on the APT. BR reportedly stated that it had derived 90% of the former's engineering from the latter. Thus, the study group recommended that the InterCity 225 be pursued as the preferred option, while the Class 89 and HST-E initiatives serve as back-ups. Despite this, the HST-E effort was promptly aborted, while Brush Traction decided to de-prioritise work on the Class 89 after learning that it was unlikely to lead to volume production. By spring 1984, favour was being given towards the adoption of a tilting carriage, tentatively designated as the Mk 4; this was viewed as superior to the existing Mk 3 and enabled a single design to be shared between the ECML and WCML. At one point, it was envisaged that the InterCity 225 would be extremely ubiquitous, even potentially having the capability built into it to operate over the southern third-rail network and within the Channel Tunnel; by mid 1984, such fanciful ideas were curtailed. Furthermore, it was decided to reduce the freight haulage capabilities of the InterCity 225, as traction for this sector was instead intended to be served via other platforms. The emergence of the , derived from the existing Class 87, somewhat reduced the pressure for the InterCity 225, reducing the prospective numbers to be built of the latter. Without tilting carriages, it had little speed advantage over the Class 90 on the WCML. It was decided to hold a competitive tender for the InterCity 225 programme; this measure was aimed at avoiding the difficulties experienced with the APT programme. A pre-qualification document was formalised, in which various requirements for the type were laid out; these included the need to perform mixed-traffic duties (day and night passenger, parcel and mail, and overnight heavy freight services), the haulage of both tilting and conventional rolling stock, a top speed of 225km/h, a maximum cant deficiency of 9° without the provision of tilt equipment, and that the maximum unsprung mass could not exceed 1.8tonnes. Furthermore, BR stated its readiness to sub-contract with the successful bidder for the supply of technical information, advice and testing. The prequalification document was issued to BREL, Brush Traction and the General Electric Company (GEC), as well as the French firm