This struck me while driving a Class 20 service over the very modest grades of TVL; it becomes much more of an issue on the hillier NTP and WSR: Under what circumstances is redlining permitted? I have been treating it as one would with a US diesel, as a no-go zone (it is permitted for very limited times, but the mechanics give you dirty looks when you turn in your logbook)- but keeping the amps in the green with an old Sulzer or EE means that acceleration takes forever (or infinity, on some uphills). Is this prototypical? Or can you just firewall the thing and hope it doesn't fly apart?
They have similar max amp limit restrictions to US locos I think. It varies from loco to loco. But most of the time full power can be used once up to 5-10mph. It depends on the situation.... I think drivers are supposed to reduce power before a field divert so there isn't so much of a jolt through the train.
Normally it’s: green - OK Yellow - OK, but not continuously for an excessive amount of time Red - don’t go there It does vary a bit between manufacturers though, with some locos having no yellow or no red zone. On the whole, if the power doesn’t trip out, you’re OK - so one way to find out is open it up to full power from a standing start, and see how high the amps go before it trips!
I used the 52 earlier and that thing was on the limiter from reading to Paddington juts to see the 90mph max
I don't believe TSW models things like genset failure or safety trips, so it's still an open question what is prototypical: staying in the green at all times (and accelerating like a slug, and never keeping to time) or slamming the throttle to the stops (which may be completely unrealistic) or something in between? Part of the problem is that it's so very easy on these locos to hit the (in-game) redline, not at all like the US diesels where you really have to be lugging a heavy train up a severe grade before it becomes a consideration.
Not all locos have a Overcurrent trip, the 47/45 do not from memory but I think all the other ones do, usually if they have a red line that is where the overload relay will trip. The 47s ratings are: Brief periods starting - 8000 Amps 5 minutes in any hour - 6500 Amps 15 minutes in any hour - 5500 Amps Continuous - 4260 Amps It should be noted that with all BR diesels, once you are above the continuous rated speed you may pretty use full power continuously since the load regulator is designed to keep current at or around the continuous rating when on full power. (it will vary slightly either side of the continuous rating but that is fine and you don't need to worry). The speeds at which full power can be used continuously for the various classes are: Class 20: 11mph Class 31: 23.5mph Class 33: 17.5mph Class 37/5: 11.4mph Class 40: 18mph Class 45: 25mph Class 47: 26mph Amusing reason why the Class 47s had to run reduced loads and the Class 56s ended up being designed, the 47s were effectively wrecking themselves due to their very high continuously rated speed of 26mph and so the heavy load + steep gradients was causing them to go through generators at a rate of knots as crews tried to get trains up to speed. The Class 56 was therefore designed with lower gearing and as such a lower continuous rated speed of 16mph. Also why the refurbished 37s had their gearing reduced from 90mph to 80mph to bring the continuous rated speed down.
So, if I am reading you correctly, then once I have reached the indicated "continuous rated" speed for the particular engine I'm driving, I can just run the throttle up to 100% and not worry about the redline? (FYI, and in refernce to the 47s burning out generators - I'm more used to US practice, which can be found explicitly on a plate mounted to the F7 dashboard; this lists in fractions of an hour how long the engine can be operated at a given output past the 825-amp redline. These limits are however cumulative, and represent maximum aggregate time before an overhaul is required; this is why the mechanics get very surly if an engineer's logbook reflects any significant overload time).
The Post of Dominus Edwardi explains it well, The max. amp doesnt say nessecary much for driving, its just that you shouldnt exceed that load. Here the tables for the max. current load of different classes (Do never exceed): Here the tables for the continuous load of different classes (useful for driving): This is from the cl.47 crewe manual (We cant isolate traction motors in tsw on the 47, so just ignore those values):
One diesel not mentioned on here is the Class 52. How would one approach managing the throttle on the Westerns?
The Western Class 52 is a Diesel Hydraulic Locomotive. Adding to much Power would result in a similar way as a steam Locomotive, where the rotary force on the wheels gets higher as the addhesion between the wheels and the tracks. Here the Cut where you can see the Voith transmission & the shafts. Pure good mechanic . Here a video of a cl.52 how not to do it. No idea if the driver was aware whats happend behind him, cant immagine somebody threating a historic vehicle like this on purpose. www.youtube.com/watch?v=r7gjYXQQN_k
