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Go Back   Railway Forum > Diesel & Electric > Diesel & Electric Discussion

Diesel "clag" ?

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Old 7th January 2022, 07:39
aussiesteve's Avatar
aussiesteve aussiesteve is offline
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Join Date: Dec 2017
Location: Bathurst
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Cooee solstice BW,
Don't go and remind me that our bonzer summer is almost half kaputt already.
Another fierce thunder boomer raged through pre dawn dumping torrential rain, thunder rattling the windows.
Aussie summer here in the Central West, PHOOEY !
And, don't go guzzling too many drams of that Bells whuskey, or you might end up with gout.
The bodgy budgie continues to moult, feathers all over the place.
Little mongrel is perched on me chair arm rest at the moment, preening and pruning.
I was gunna pop down town today to do a hunter gatherer.
But, the plague news on tv is HORRENDOUS.
Yesterday we copped in excess of 80000 infections in the country, naturally NSW being by far the worst.
With a total population around 2.7 times LESS than the UK, that puts our plaguers WORSE than in the UK yesterday.
So, I am still hiding in the hovel today.
Not to worry about the green plastic manual lack of specifics.
From googling there appears to be little in the way of specifics available freebie on the www.
I did encounter one webby mob who provide various BR etc manual pdf files freebie.
British Railways Engineering Training Manuals.
https://www.silvermoorconsulting.co.uk/
While there is no BR class 37 ops manual, there are some other interesting manuals.
My el cheapo home www was only just able to snag a couple of them.
One being the BR Drivers Manual General Data for various weasels.
This details the basic specifications for each weasel, including the class 37.
Including there being the pair of Turbo exhausts.
Full power being available between 10 to 79 mph, with minimum speed at constant rating being 13.6 mph.
AKA 13.6 mph is the balancing speed, whereby the loco can such maintain endlessly.
Getting under 13.6 mph when at full power on a gradient could result in entering short time ratings.
Plus potential for wheel slip and an ultimate stall.
The balancing speed is used to determine the max load capacity on the ruling gradient for that weasel.
Plus also if any load reduction is necessary when multipled with a lower balancing speed weasel.
Here we reduce the total train load possible by 10% when a lower balancing speed loco is multipled.
AKA, a 44 class can drag 615 tonne up a 1 in 40 at 19 kph.
Whereas a 48er can drag 410 tonne up a 1 in 40 at 13 kph.
Multiple a 44 with a 48er and you simply cannot bung a total of 1025 tonne on the pair.
The combined train load must be reduced to a max of 922 tonne or risk stalling.
Class 37 continuous traction amps of 600 with a short time max rating of 630 amps for one hour.
Though, other higher amp limited short time ratings are not included.
This kinda infers to me that in yer video clip the class 37 hogger is notching up and down repetitively.
Constant full power at 10 mph with a heavy train on a grade could create wheel slip.
And would definitely start to enter short time ratings.
Short time ratings are accumulative.
So, once achieving the absolute MAX amperage for the very short time, you must reduce throttle notch.
To avoid going back into short time ratings.
With a heavy train on a gradient, reducing throttle notch for any long period could result in the train stalling.
This is why AC traction weasels are now so popular for heavy slogging at slow speed.
NO short time ratings.
The EE sweep controller that I mentioned has 6 positions, NOT notches in the true sense of the meaning.
B = dynamic brake increase.
L = dynamic brake hold (lap)
D = dynamic brake set up minimum amps, plus step down in dynamic oomph
0 = OFF (both power and dynamic)
MINIMUM power position.
Then sweep through to MAXIMUM power position.
These positions being in a clockwise direction of the handle movement from B to Max power.
I did enjoy playing with them Van Demonian EEs once I became accustomed to their idiosyncrasies.
To engage dynamic brake you move the handle from O to D and await for amps to occur and settle.
Then move through L to B to increase amps.
Then move back to L to hold that dynamic brake amp setting.
To again increase dynamic amps, move to B and then back to L.
To reduce dynamic brake amps, move to D and allow amps to reduce according then back to L.
To disengage dynamic move from L to D and allow all amps to reduce to minimum, then go to O.
When powering move from O to the minimum traction amps setting and allow to settle.
Then sweep the handle to a desired traction amps demand.
All the way to the Max position if necessary on a steep grade with a heavy load.
Traction amps will then begin to cycle.
The class 37 having Westinghouse air brake system.
Whereas the Van Demonian Y, Z and ZA class EEs had Davies Metcalfe air brake system.
The ex QR blow-in EEs, ZB and ZC had Westinghouse air brake system.
I have a photo of the Tassie Z class cab controls in the forum.
http://www.railwayforum.net/gallery/...imageuser=8578
EE sweep master controller and Davies Metcalfe M9A air brake.
OH, and That BLUE fault lamp.
Here on Alcos and EMDs, a blue fault lamp indicates a failure of the Auxiliary Generator / Alternator.
The Van Demonian Z had a belt driven auxiliary generator.
The Van Demonian ZA had a belt driven auxiliary alternator.
But, from memory there was no equivalent to the Blue fault lamp.
Instead there was a Battery Charging fault lamp which would give a similar indication.
All of the Van Demonian EE fault lamps were red.
NO Bells and whistles here.
Only apple cider, red plonk and a smidgen of vodka.
Steve.


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