Alco 48 class loco pics

Quote:

---

Originally Posted by PAT303

Tim,I've been reading up on loco's,why do they use DC motors?,some of the American ones also use AC so whats the reason for it?. Pat

---

DC was used originally because of the availability of adequate speed controllers. Suitable speed controllers for AC current were a much later development. Of course, once a dc system had been constructed, the system had to be kept in operation as the alternative was to demolish and start again. Hence Queensland Rail, coming late to electrification built an ac system.

For those interested, many Queensland country towns in the days of town power stations before the state grid, had reticulated dc. Somewhere I have a 1950 directory that lists services available in most Qld. towns and map spots on the rail lines. The listing shows (rail) distance from Roma Street, population, availability of water, sewerage, gas, electricity and what type, local authority,etc. I can dig it out if anyone has a question.

Hi Brian, while your right about ELECTRIC rail networks, Pat and I are talking about the traction motors and controls used in DIESEL electric locos.

The introduction of AC diesel electric locos is something relatively new. GE started producing them about 15 years ago and EMD ( General Motors locomotive division ) are now producing AC versions of their diesel electrics as well.

Quote:

---

Originally Posted by drivesafe

Hi Brian, while your right about ELECTRIC rail networks, Pat and I are talking about the traction motors and controls used in DIESEL electric locos.

The introduction of AC diesel electric locos is something relatively new. GE started producing them about 15 years ago and EMD ( General Motors locomotive division ) are now producing AC versions of their diesel electrics as well.

---

Most likely the same reason, adequate speed control of the electric motors.

GM sold EMD about 2005, by the way.

Great pics Drivesafe!,where did you get them?,no wonder the poor buggers down the hill got clobbered:(,thats a lot of water going flat out!.We were lucky in Brissy,most of our stuff just got wet and a bit muddy,a few points machines are cactus but all in all pretty good considering:eek:

AC locos also have amazing traction at low speeds and pulse the traction motors when struglling for grip,helping the wheels bite the rail;)while using little sand,it's awesome to see close up!!!the whole loco bounces as it inches forward with very little wheelspin,clever things.
A clip of some 48's at Weris ck-
YouTube - FishplateFilms's Channel

Cheers Gregg:)

Jumping in late, but a very good thread.
Spent my youth in the late 60's going to Central each Sat morning and asking any outbound diesel operator for a ride. Never disappointed. Usually a 40 on the North Coast Daylight, a 44 on the Riverina Express. Forget the others. Rode to Strathfield, returned and maybe got lucky again. Got a ride around the Central shunting area in a 32 once.
Used to go to Wauchope and return each summer on the Daylight. Seemed to be the home of the 40 and 43, sometimes a 44. Always got a ride up front at some point. Driver change at Taree so if you missed one then....

I recall the 40 had like gears? - did the driver have to do throttle, power back, engage something and power up? What I remember anyway.
Remember coming home with a 43 that broke down somewhere where a spare 44 was waiting to rescue us as we weren't sitting long. Then at Gosford? we got towed home by the usual 46. Quite a site getting off at Central and seeing the 3 of them. A 46 always towed that train into Central anyway, but with the 2 diesels it was cool.
I lived around Tempe.
The train to Woolongong I guess was always pulled by a 48. There is a straight run into Tempe from Sydenham where it could get a good run, then throttle back round the bend into Tempe and thru platform 4. Then hit the throttle for a nice run to Arncliffe - clouds of smoke, great sound. Always stopped to watch.
I would live to hear a 42 start. Sometimes my Sat morn would be at Central Platform 1 where the Melbourne train had usually a 42 - maybe 2?
They never seemed to use the 42 on the North.
Riding home from Canterbury High we always passed 405 South goods train. Always 2 diesels, and usually 44/45 but now and then a 42.
Always hung out in Marrickville past the station where the goods line branches off and goes to the goods yard over yonder. The trains always stopped at the points and the drivers would always let you hop on for a look. Recall a few steam - a 36? and the 32 of course. Had a look at a 422 there brand new I recall. Never rode from there.

G'day all,
As promised at the start of this thread,I;ve finally put the videos of my trip behind the two 48's around Bethungra Spiral,and from Coota' to Junee in the cab:D,better late than never:eek:
YouTube - FishplateFilms's Channel

Cheers Gregg;)

I forgot to answer your question Allan!,the traction motors on diesel electric locos have two sets of windings,one winding in series for greater torque on start,and the other in parralell for higher speed.Early locos didn'thave advanced switching between the two, so drivers would notch up the to required speed,then back off so the contactors could change without high current (hundreds of amps!!) passing through them:eek:.This soon changed to automatic transition as technology improved,similar to star -delta starting in three phase motors.Modern AC traction locos use a very advanced 3-phase motor control which gives incredible traction with reduced wheel and rail wear while using less fuel.Some good stories from your past there:D.
Cheers Gregg;)

Damn. I must be getting old ...... I can only remember steamers on the daylight express. :(

I know these aren't 48's but......
A pic of CLP13 built in 1970 (not sure what CLP# the second loco is) on the maiden wheat run for Aussie Southern from Coota, leaving Goulburn station and dead in the water right in front of my home. Something to do with an earth breaker tripping. That's what happens when you name it 13! Further proof in the second pic.


http://www.aulro.com/afvb/attachment...1&d=1304511472
around 01/2005 at Goulburn.

http://www.aulro.com/afvb/attachment...1&d=1304511668
around 01/2006 at Sefton.

Cheers,
Daz.

Hi Daz
Nice pics,the CLP's are a favourite amongst Railfans,big and loud,and they're still working all over the place,get them up in Brissy occasionally.I'm in the process of putting some footage together for you-tube:)
Cheers Gregg;)

Quote:

---

Originally Posted by circlework

Something to do with an earth breaker tripping.

---

Glad the same thing doesn't happen with a bad earth in the Disco.