As we know, UP Big Boy 4014 runs around with a diesel locomotive that performs several tasks, notably assisting it on steep grades. Is there a diesel loco that works in this manner with the Flying Scotsman within game mechanics? Some pretty steep hills and I'd like to make it up some of them without dropping into the teen region of the speedometer.
The primary function of the BB's accompanying diesel is (1) fuel economy. These days there simply aren't water towers every 25 miles and coal every 75. So keeping the diesel pushing in notch 1 or 2 greatly reduces how much regulator the BB needs, and how much train food it eats. (2) wear and tear. Steam locos require a LOT of maintenance. There used to be sheds and roundhouses at every yard with armies of technicians to service them. Now? BB has her crew she carries, and whatever parts she can carry- you don't want her suffering a major malfunction before the end of the tour. Again, having the diesel allows it to work less hard. Trust me, BB doesn't need a helper just to climb a grade.
I'm not really surprised at all. BB is a freaking beast of a loco. I didn't think about the fuel/water consumption at all. While heavy fuel oil is a lot more portable than coal, it would still be a B and a half trying to refuel it. I do kinda wanna replicate the setup for the Scotsman, though I'll absolutely use it for the steep hills too, cuz that guy doesn't have a whole lot of torque compared to my usual standby the Class 47
Some UK steam excursions will run with a diesel on the back or sometimes coupled inside the kettle. But that’s generally as insurance against the steamer conking out or to make shunting moves easier.
In the UK the diesel is there for breakdowns as mentioned, areas that are a high fire risk and they can't run the steam engine. Also the many places that don't have a loop to turn around.
Is this the primary use case exactly? It's like saying the main purpose of a towel is to be paint on by a kid, sure, it can be, but that's hardly the purpose of it! I've never heard that as the primary purpose per-say, on the contrary Ed has directly stated it's actually been used to make the engine work more hard over the years. Explained further recently that's actually to give the fireman more smoke to work with to make their job easier. Link to the full Trainorder's post for the curious. I don't have any direct links, but also I know he's stated at multiple train shows they like using the brakes on both the diesel and the consist to help conserve the brakes on the Big Boy itself. Which incidentally also explains why you sometimes see the Big Boy run with assorts of cars as opposed to going light everywhere. Making new brake pads ain't as common as it used to be, the ones for the Big Boy I think are non-standard, adding to the cost, and it's a quite involved process to replace them I believe, so best not to do it more often than needed. They'd rather use up the brakes on more standard equipment like the diesel or random hoppers as opposed to the "crown jewel" of the fleet. More in line with what you're saying, but still very different from the use case you've talking about here.
Apart from being able to push in the event of a breakdown, I thought the primary purpose was to provide Electric Train Heating to the coaching stock?
However, very often on UK railtours the diesel loco is under power. The claim is that the loco only generates enough power to overcome its own weight, but it’s impossible to achieve that consistently, and in reality the diesel loco is assisting the steam loco to different degrees at different times. As a result, it’s impossible to know how the steam loco is performing - which, for people like me who are interested in such things, is a great shame. For me the interesting thing about steam engines is not just that they look nice and make an impressive noise. It’s the genius of the designers - all those years ago - in creating a machine which can generate such power from coal and water, and it’s the skill of the enginemen and women who know just how to get the best out of them. Comparing the performance of different locos and crews on different routes has always fascinated me. As soon as you stick a diesel on and have it under power, so that you can’t know how the steam loco is performing, it kind of loses its wonder. It also looks awful having a diesel swinging about on the back of the train - to put it in sim terms, it ruins the immersion… I’ve stopped going on steam railtours since the practice began.
True for 2021 to 2023, but wasn't the case in 2019 (PTC wasn't equipped, but also wasn't needed) and they got it a standalone installation last year, so the diesel's now entirely optional. Quick edit. Can't speak for the UK, but the freight diesels UP have I don't even think could power them even if they wanted to, they use dedicated power cars for that reason.
You could call the diesel a necessary evil. I'd rather that than nothing at all. Even with the diesel assisting, up on the footplate of the steam engine nothing will change. The crew still have their work cut out. The engine itself will still be doing most of the work.
I dunno about the Scotsman in particular, but a documentary I was watching on the Big Boy and other steam locos said that they use the diesel to give resistance to the steam loco so it looks impressive chugging heavy even on a flat surface. The railfans and crowds love to see her "working" so they rev the diesel up for artificial resistance. I think they also can use it for long distance to save wear and tear and "saving it for the shows" kind of like classic cars ride around on trailers to the car shows. In theory you could use it for hills, but most steam engines can handle any hill with just the light carriages they are pulling. If you want to test it, just do a run up Cajon Pass with the Scotsman and 3-4 carriages to see what I mean. That's over 3 percent and it runs fine. There's really nothing that steep for an extended duration in the UK for it to tackle so there's no way it'd be needed for grade. Interestingly, the original purpose of the diesel should be in theory applicable in TSW too since you could put a diesel in opposition and get the Scotsman working harder for more impressive pictures. The exhaust physics should still make that work.
