In all honesty speaking here. Those mods would work out cheaper than buying a brand new locomotive. Another argument that would make a rebuild viable is that the FTOC such as DBC wouldn't have to pay for shipping costs of importing new locomotives plus import fees to take into account so that is another cost effective saying. Also as all the DBC drivers I am assuming are type-trained to drive a Class 60. So with that refurbishment package. More costs would be saved as type-training would not be needed unlike with a brand new locomotive. Another thing from what I have learned from the DBC drivers that I have spoken to in the past is that the Class 60's are much nicer to drive than the 66's as the PU isn't bolted to the chassis and doesn't vibrate the cab or is as noisy. Also it could be a new start of producing our own locomotives again as the Class 60 rebuild with the new traction equipment and stuff on one locomotive could pave the way for Brush to start making locomotives again as better technology is more available now than it was back in 1989 when the only EMD locomotives around then were the fairly new and successful Class 59's.There's all manner of problems with the Class 60 locomotives, the engine is a known issue but with some modifications, it can be relatively reliable, though you'll never match the reliability that a simple two stroke diesel is capable of.
Re-engineering was considered previously and ruled out on grounds of cost, today it's likely to be even more complicated thanks to the emissions legislation - expect bodyshell modifications (difficult with a monocoque) to allow a Euro IV compliant engine to fit into the existing bodyshell.
It's not just the engine, you would want to replace the slightly fragile DC traction motors with much more reliable, lower maintenance AC motors, but that's bogie modifications too. The engine could dictate a new traction alternator too.
Which then leads to a whole load of new control equipment to manage the new motors, alternator and engine.
Then you've got to strip the bodyshell down, effect corrosion repairs, strip bogies, make modifications. It starts getting stupidly expensive and before you know where you are, you've spent the same as it would cost for a new build locomotive from Stadler/Vossloh or GE.
That's why the Class 57 program didn't really go all that far, and it used scrap alternators from Class 56s initially, refurbished ex US Navy engines and kept the same motors etc. It's just not cost effective.
In regards to the Class 57 project. Wasn't that just a stop gap for Freightliner originally until they got their Class 66's? Virgin had about 20 of them for Thunderbird work. But in all honesty here. Comparing a Class 57 to a Class 60 for haulage power is like comparing a saloon car to a truck unit hauling a heavy load . A 57/0 would seriously struggle to haul a rake of 30-32 tank wagons that is the same syndrome of the Class 66's as they just lack the setup and power that the Class 60's have for this heavy work.
Why should DBC do that? I was surprised when they performed the Super 60 refurbs on the locos that Colas were allowed to purchase, but DBC must have had their reasons (notably financial). I daresay they charged a healthy premium to Colas for that work.
Again, we can thank politics for how Wisconsin Central acquired their fleet of locos. Unlike passenger locos that generally passed into the hands of the ROSCOs at the time of privatisation, EWS hoovered up the existing loco fleet along with the businesses they purchased. This has now manifested itself as a fleet of 58s in Spain with no likelihood of return, dozens of 60s rotting at Toton and even 90s parked up with no work, all under the auspices of one FOC. If only the 58s, 60s, 90s and 92s had passed to the ROSCOs ..... again, fantasy thoughts with the benefit of hindsight!
Why shouldn't DBC do that? . They could make money from other FTOC's that choose to rent the Class 60's from DBC and that would keep the money flowing into DBC's wallet whilst the other FTOC that leases them gets a powerful decent locomotive that won't break its back under a heavy load. Also in regards to the Class 60's and Brush Traction. I think it is time that Brush Traction should start making its own UK built locomotives once again rather than TOC/FTOC's being forced to rely on imported locomotives. Britain invented the railway originally under George Stephenson and I find it somewhat appauling that Britain no longer produces its own Locomotives.
Meanwhile if Brush can bring a HST like 43101 back from the dead with new parts and stuff. As 43101 did spend a long time on trestles when it was withdrawn from Virgin back in 2003 and didn't come back into service until around 2008. It now runs with CCT as 43301 since its refurbishment and I think it is still going strong today under MTU power .
So perhaps Brush could make a new locomotive based on the Class 60 design and maybe build a prototype using one of the "dead" Class 60's such as 60006, 60008, 60064, 60070, 60081 and/or 60098 as a base and test bed for their new locomotive . Because didn't VivaRail make a DEMU from some much older D78 Tube Stock just recently? As viewing those scenarios alone proves that anything can be obtained and if Britain starts to build its own trains again. That would give the economy a boost in the right direction as more jobs would be created.