Pusher locomotives in hard dynamic braking on BNSF coal train Padromi, Colorado

This BNSF coal train was moving at a pretty good speed when it suddenly went into hard dynamic braking. The pusher locomotives are really howling on this train.

[@TrainmanSky]

My god! The thing is though it’s weird because when you hear a full throttle pair of emds struggling on an upgrade they just sound like emds, but when their in full dynamic mode even gevo’s sometimes will give off that actual “jet engine” type sound when they pass by. That’s awesome dude

[@fritzd2116]

Wow. The deacceleration was very noticeable. Nice to see 70 MACS back on BNSF trains, also!

[@ackmino]

9750 is an upgraded MACE. Has same computers and software as an ACE along with Mitsubishi inverters.. but I agree, nice to see the MACs back.

[@skiiipawbs]

Isn’t the dynamic break just the traction motors being used as a generator?

[@ackmino]

@@skiiipawbs on a DC locomotive yes. On AC locos with inverters, the motors are getting the 3-phase windings retarded and put back on the DC grid. AC is very complicated actually. Both DC and AC systems need a field current from the main alternator for dynamic brakes.. I probably didn't help you much..

[@skiiipawbs]

ackmino so what your saying is on the dc locos the traction motors are used as generators but on ac the electricity being generated is spit back out across the terminals? Do ac locos even have dynamic braking? You did answer my question but I have another one. How does it slow down? I’m confused.

[@ackmino]

@@skiiipawbs AC locomotive have superior dynamic braking. The 3-phase inverters are taking DC power from the main alternator and retarding the motors. The power coming back from the motors is going back on the DC link and dissipated thru the grids.. I know you are thinking this is impossible.. I had 10 years electrical experience on locos and most of us couldn't believe it worked.. engineers cant explain it either.. I should send you a schematic somehow?

[@TheBhartiyaTrainee]

Awesome! Greetings from India!

[@RickyJr46]

Good stuff!

[@AMNRailway]

Muy buen video! 👍😀😀

[@juliussuilujwilsonnosliw7999]

Five locomotive one hundred and five coal cart times one twenty's tons per trains equal 12,600 tons times 2000 pounds equal 2,520,000 pounds

[@SvenTSchixe]

25,200,000 lbs You forgot a zero, lol

[@Jesuscatshockey]

Listen to noise. Air brakes used too.

[@ragedeeann644]

#debrief Ok, I'm usually Boogara, but with a Shaniac detective brain, so I guess a 💩 🐟 (do we still use that?). Anyway, Shane is 1000% percent correct in that most of these are freight train brakes, which take about 2 mi to fully stop. Source: I hopped freight for over a decade. Edits: Also, some of the other ones sound like after a jet breaks the sound barrier? Ok the 2012 Alberta one got me shook. And my dog don't like it.

[@valdecibessa5362]

How those brakes working?all off them goes at same time

[@travelingtom923]

They normally start at the front and work towards the back. With locomotives in the rear however the brakes would apply at the front and rear locomotives and work towards the middle of the train.

[@MachineHeadDissent]

Damn...lost count...how many???...

[@lemontiepyle2421]

Screw that. Use your head end dynos only and set some air. Using rear end dynos puts you at risk for busting your train in two.

[@jacobhoward7460]

If you break a unit train in two, you should find another career

[@michaelo1929]

I use dynos on the "B" consist all the time. Just have to know when and where to use them. Been running over 20 years now and haven't broken a single knuckle (knock on wood).

[@cajentertainment2516]

Another keyboard expert

[@ThePaulv12]

Watch from 2 mins 30 sec: kzbin.info/www/bejne/e3TTe5xsm650h8k