Dog Star
Western Thunderer
Told you so, even the Flying Squad gets confused...
regards, Graham or Barking dependent upon who takes the biscuit.
Told you so, even the Flying Squad gets confused...
regards, Graham or Barking dependent upon who takes the biscuit.
Ressaldar
Western Thunderer
Told you so, even the Flying Squad gets confused...
regards, Graham or Barking dependent upon who takes the biscuit.
but you are always taking the biscuit Graham
cheers
Mike aka Ressaldar or putting it another way Ressaldar aka Mike
Dog Star
Western Thunderer
mickoo
Western Thunderer
It's called weight transfer and quite a few locos do it, especially the more compact short wheel base variants, it's a major problem these days with heavier trains, many locos now use electronics to decrease the power to the rear motor (not applicable to hydraulics of course) to stop it digging in and tilting the bogie. Of course this works best with AC motors and their individual inverter drives, DC motors still tend to all be fed from one bus (armature) making individual motor control quite complex, but it can be done through field control. Some designs use hydraulic rams to push the nose of the bogie down, others use complex outside torque bars and linkage to achieve the same (SAR 8E class).
It's now such a big problem in the US as they have reached the limit of adhesion with Co-Co's even with individual motor control and super creep, the lastest technological leap to eliminate weight transfer is lifting wheels and thus increasing the loco weight for the traction wheels and increasing the effective length of the wheel base. GE has developed with BNSF the ES44C4 with is visually a Co-Co but only 4 powered axles, in effect a A1A-A1A (aka class 31), there's more than enough power in the 4 motors to meet adhesion levels. In super traction mode the inner axle is lifted via linkages (externally visible) to increase the weight on the outer powered ones. It must work as BNSF have an order for over 1000 of these!
Closer to home the class 86, 87 & 90 with flexicoil springs visibly move under acceleration, obviously having braked into a station the bogies are pushed back and the springs flex rearward, on starting the bogies move forward, past mid point and toward full forward, if the bearings and traction links are worn it could be 6" or more.
/End] OT technology diversion
mickoo
Western Thunderer
LOL, your previous description conjoured images of Wezzies doing a sort of Sumo squat before launching off.
S
SteveO
Guest
I have another question: how does DCC know what gear ratio you're running - and therefore the scale speed you're going to portray the correct engine tone?
These are probably quite stupid questions but after looking for an answer on various pro DCC websites it doesn't explain how this works. The only answer I can guess at is that it 'assumes' the ratio you are 'probably' running and uses the rpm or feedback of the motor to guess the speed. Am I close?
These are probably quite stupid questions but after looking for an answer on various pro DCC websites it doesn't explain how this works. The only answer I can guess at is that it 'assumes' the ratio you are 'probably' running and uses the rpm or feedback of the motor to guess the speed. Am I close?
Steph Dale
Western Thunderer
Steve,
Unfortunately not....
To get it working properly you first have to get the decoder sound profile set up to either diesel mechanical, diesel electric, diesel hydraulic or steam. This is part of the set up of the sound so not usually user tailorable.
Then you set up the loco and get the decoder installed and running properly. This is on CVs, usually a few; sometimes (as with ESU) the decoder can learn how the motor behaves. I tend to do this with the decoder on silent or no speaker attached.
Then you set up how the sound will perform with the drive - notching for diesels, beats per revolution for steam and also an element of how you want the drive sounds to 'play' as the loco moves. This latter point within the constraints of whatever is in the sound profile.
An' that's it - as far as you or I are concerned it's all down to how we set up the CVs...
Steph
S
SteveO
Guest
Steve,
Unfortunately not....
[stuff I didn't understand]
Steph
I can see we are going to be doing a lot of chatting over the coming months! Cheers for the help so far, much appreciated.
ZiderHead
Western Thunderer
Probably the same word used by Swindon to describe anything not built at Swindon, perhaps..??!!
Ive always suspected that this attitude was the real reason that the last CL22 earmarked for preservation was "accidentally scrapped" at Swindon works ...
S
Simon Dunkley
Guest
They weren't above doing it to their own work, though - "North Star", anyone?Ive always suspected that this attitude was the real reason that the last CL22 earmarked for preservation was "accidentally scrapped" at Swindon works ...
Phill Dyson
Western Thunderer
...& 818 Glory
, from this in 1985 http://farm3.staticflickr.com/2328/2277766867_2ba1e390b4_z.jpg ...........to this a month later http://www.railblue.com/Pictures/Class 42/D818_SW_1985.jpg
, from this in 1985 http://farm3.staticflickr.com/2328/2277766867_2ba1e390b4_z.jpg ...........to this a month later http://www.railblue.com/Pictures/Class 42/D818_SW_1985.jpg