Right when you went to start talking about the engine protector, I was fully prepared to be a pedant in the comments section lol. A couple snippets from me are all I have though. 1: The hot oil detector and engine protector both work by causing the governor to sense low oil pressure, which as you said makes it shut down. The hot oil detector is a thermostatic valve, (like a thermostat in a car or truck) which opens at, I believe, 215 degrees Fahrenheit. When it opens it dumps the oil in the governor's sensing line causing the low oil shutdown to pop. The actual valve for that is located in the main lube manifold going into the front of the engine. 2: You mentioned a sort of "limp mode" and actually even those old locomotives have something similar. When you look right above air compressor and towards the front of the locomotive you can see a water manifold. That manifold has three temperature switches in it (a normal SD40-2 would have four). The switches are labeled TA, TB, TC, and ETS. (A tunnel won't have a switch in the TC spot since they only have two fans.) That ETS (engine temperature switch) picks up at, again *I think,* 205 degrees. When that switch closes a bunch of electrical stuff happens and it "derates" in a sense. It basically changes your throttle notches to 1, 2, 3, 4, 5, 6, 5, 6. (in 7 & 8 it knocks you down 2 notches) the speed reduction reduces the risk of cavitation in the water pumps, and the excitation system reduces the load on the engine as well. Not anywhere near what modern electronic controls are capable of, but still a neat little "limp mode" even on those old engines. So yeah, that's the pedant in me satisfied lol. Great video and definitely earned a like from me! Also, I'm sure you remember me from last week and I did check and according to the source I looked at, our 5413 retains the number it had when it ran on the D&RGW, and the 5412 used to be the D&RGW 5391.

I was hoping to see a piston going to space in the clip that played after the discussion of crank case overpressure

Would love to see both 5401 and 3011 featured in a loco 360

Hey Hyce....5401 was a good unit, Mars light and all. Operated her back in the late 70's out of Denver. She is an old lady now, and shows it. When she was new she was proud to be a leader amongst the GP30's, GP40's, and SD-9's, SD-40's, and SD45's in the stable. These were, as you know, used primarily on the coal trains to Phippsburg, and beyond...to Craig. They had a very eloquent style. Will always be my favorite locomotive type...(they could really haul...at the lower speeds), and the dynamics were easy to control. Mitch Pittenger (Road Foreman) was a buddy (god rest his soul), and we had some great times railroading together. Thank you for the look back into the past !!!

I really really want to see more "Nerding out" with Hyce on an EMD locomotive. It may not be Steam, but the BNSF story juices can start to flow and experiences as the camera films Hyce show and talk EMD locomotives with this SD40-2T.

The Colorado railroad museum is on the list to visit some day. I've always thought the tunnel motors were a great series and such a simple way to approach the problem.

I loved our SP tunnels. We had 45t-2s and regular 40t-2s. Crews would often brag about how good "9500" and "9400" were at pulling. Sadly the tunnels are all but gone, with the last one "4071" breifly going into the deadline before being returned for a short time as a new customer needed a dedicated engine. She found her way into a few more road trains as she came in on her 92 day and the customer realized a big 6 axle was too much power for them only to finally end up leased to a grain elevator after one of their workhorses went down. Its unclear if 4071 will ever return to our roster or will remain at the elevator the rest of her days.

it’s cool to see old engines like this

645 c.i. per cylinder comes out to 169.1 L!!!! I understand that that's not super surprising to most train nerds, but to me, somebody who is just learning about how diesels work, that is utterly astounding! Great work, Hyce! Love the content.

Hyce: Do you want to see me go into nerdy details of locomotives in video form? Everyone here: But that's why we're here, so obviously yes! Also everyone: With the Hyce special touch of teaching train tech, who would want to miss out!

Id just like to say Mark, im happy to see how much you’ve grown your channel over these 2 years. Ive been here since u started the original RO play throughs. Cheers to you, keep on rollin man.

Was about to comment about how the SP developed the tunnel motors, but it looks like you beat me to it. 😁 That said, Moffat tunnel is no longer the second longest in the US, it's the third. Flathead Tunnel in Montana, built in the late 60's, is second longest at 7 miles. It was built to reroute the GN Hi-Line when Libby Dam flooded the original route.

I would love to see a Loco 360 on this locomotive!

A 360 would be cool and I think maybe a 346 step by step once in a while would be cool to

Very cool video! The SD40T-2 has to be my favorite EMD locomotive of all time. My grandfather worked for the SP and worked with these all the time, despite there being no tunnels on the SP route through Arizona, although they did work Donner Pass and throughout the Sierra Nevadas. Said they were fantastic at what they did. After the merger, he also got to work on former Grande ones and on the former DRGW lines, including Moffat Tunnel!

Yeah, this is an excellent opportunity to do a full, in-detail workover of the locomotive. As a side note, I really enjoyed that you admitted you were incorrect and offered corrections. Shows your humility. Nicely done Hyce.

You know, I was just asking myself last week if you had covered the museum's tunnel motor. Lo and behold I get this in my recommended! Beautiful explanation of the functionalities! Our railroad has 3 tunnels, two of them still retaining the original Rio Grande livery! 5391 (now 5412) and 5413! As a side note, sanding these things are a pain, especially if there are two of them back-to-back :L I just love trying to reach for the sand hoses that have been set up for regular 6-axles and the occasional 4-axles when these long bois come in. Stretch Armstrong mode activated. And don't get me started on those long hood suicide steps .-.

You're hilarious, that's how you send pistons to space. Awesomely put.

Those SD40s may be old and outdated but there are very few locomotives that I prefer when it comes to flat switching.

The Ringneck and Western railroad out here in South Dakota has a tunnel motor running on their line. It looks a little silly being there no tunnels, but it's a cool piece of railroading history.

Another banger of a video from Hyce. I’ve never been happier to be subscribed as I have been lately. Fantastic content. I’d thoroughly enjoy a 360 video of this loco, and more!

A tunnel story. My dad fired for the B&O out of Baltimore, West End. The route west, the Old Main Line, winds it's way up a river valley, cresting the grade at a place called Mount Airy, Md. The line summits through a mile-long tunnel under the town. Not that steep, but for a train, gradient is relative. The trick to firing through a tunnel is to have the boiler full, and the fire-box as hot as possible with plenty of coal. Before entering the tunnel the feed-water is shut-off, and no more coal added to the fire. With luck the train will be over the hump before water and coal must be added. Often the water in the sight-glass would drop out of sight. The story The engine wasn't steaming well. Not only did it require almost constant feed-water, it was burning more coal than it should, and was filling the tunnel with exhaust. Then they stalled. My dad looked over at the engineer. The engineer was on the verge of passing-out. My dad suggested to the brakeman to get down and pull the pin, they had to get out of there. He went over to the engineer, shaking him and yelling, "Give the brakeman some slack, we're cutting-off and getting out of here." Tunnels and fuel-burning engines are fundamentally incompatible. If tunnels had desires, it would be to kill humans. I am sure that Hyce has a copy of "Rails that Climb." The Moffat trains faced snow-shed hells.

I love these videos, this is stuff I would have never been interested in since I'm more of a continental european electric loco guy but your presentatnion manages to make this stuff incredibly interesting.

you are literally one of my fave people to watch talk about things, not for the topic (although interesting), but for the way you structure the video, the method, the context, the sass and the wit. you truly are an intellectual pleasure x

Would love to see a 360 video of it. The sd-40 and dash 2s are amazing locos and so much fun to operate

I was actually learning about Grande 2nd gens like this just before this came out! Keep up the great work helping common civilians learn about this great industry!

When you said send a "piston to space" I was a little disappointed when that next video clip, wasn't an example of that happening.

Another great, interesting, and informative vid, Hyce. Keep 'em coming and I keep watching. I really enjoy your channel .. thanks.

You guys are a crack up.... Great info and love the delivery of the video..... 🤙

Your videos are awesome. I love the content. 👍🏼

As much as i appreciate the videos you do on locomotives, i most definitely appreciate the honesty you have when it comes to mistakes! Very cool!

Just found your channel I really enjoy the videos. I was a locomotive engineer for Conrail and then CSX. Best most fun job I ever had.

My dad was one of the lead design and manufacturing engineers for Motive Power out of Boise, Idaho up until just before they went bankrupt from poor account management. I can’t wait to show him your channel. He will tell anyone who will listen that “working on choo-choos” was the best job of his 45-year career.

We have a pair of these in my home terminal in Fond Du Lac Wisconsin for CN. We use them as shover power, and I always wondered why they have a huge open space in the back. Thanks for finally answering that for me!

You know, seeing you next to the loco Hyce, reminds me of how huge the US equipment is! Our stuff only go as high as the nose of your locos. That's one reason I want to visit the US, just to enjoy the size of the trains!

Great video look at one of my all-time favorite locomotives. Thanks for creating it. 👍

Loving the channel information and content thanks for the uploads

Far away shots alongside the close shots to maintain perspective is awesome, thank you!

Love the new camera angle. I always wondered what the POV of Hyce's coworkers were XD

A HUge Big hanx for an AWESOME explanatory doccu info about the big iron we ALL LOVE..love and respect from denmark

Thanks Mark another informative video, i've learned so much more on one of my favorite subjects, TRAINS !

You are great at explaining trains! Awesome video

I remember seeing these as a young kid (in SP livery) and noticing they looked different. It wasn't until a couple of years ago I learned what they were. This video does a great job of showing the equipment that makes it a tunnel motor.

Awesome show, I always wondered how these worked, very nice and thorough explanation !!

"You do not want crank-case overpressure... That's how you send pistons to space." Watch out, Hyce! Jebediah Kerman will be looking into piston-launched rocket technology next!

This is some of the most fascinating content imo. Nerds love to see how stuff works!

Those old converted rail trucks (car/vehicle) are amazing... Would love to see all the trains but those are super interesting , ive never seen any that old and they look in really good shape

Pretty closing music! Thanks for your expertise Hyce!

Was just thinking about tunnel engines used by SP, and bam! up pops your video! Thanks for taking the time to show us exactly how the “T” engine concept worked. Great video!

Love the Video Hyce, Tunnel motors are my 2nd most favorite modern unit. We had a bunch here in Southern Oregon after the DRGW/SP merger. I lived next to the old SP Siskiyou line in Roseburg, Oregon. Loved seeing them running all the time and then when CORP took over and went Red/Grey livery and got 3 of them. I now model this line in HO from 04-06ish

That was a great explainer and something I'd never even thought about. Thanks 😊

Great video. The production value reminded me of those "All About Trains" VHS and DVDs from my childhood

I love this video because I've always understood how a tunnel motor operates, but I've never known how it's all put together to actually do the cooling. And yes, please do a Loco 360 on it!

Would love to see 360 on 5401 I have always loved the tunnel motors and would enjoy seeing more. Thank you hyce for what you do and being an amazing person that shares their passion with the world around them

Very interesting and cool video you make learning fun. Thanks a bunch.

Great stuff! SD is my all time fave in diesels n ya learned me some things Hyce! Cheers from Santa Cruz ca

The DMIR ended up buying several of the SD45T-2 rebuilt into SD40-3’s.

Thank you for a great video. Your passion for railroad shows in your work.

Fantastic video. The biggest class II out by me "Wheeling & Lake Erie", has two of these operating in Rio Grande paint still. I have a good video of them from August 23rd this year.

Great subject. I’m a SP/DRG&W fan. I just joined. Keep that good content coming.

Your video just popped up on my feed....watched, liked and subscribed! Any mountain railroading, is GREAT railroading! I'm huge fan of the Milwaukee Road, with a soft spot for the Rio Grande! Greetings from a Swede in Glasgow, Scotland! 🤜🏻🤛🏻🍻

Very informative! Thanks for taking the time to do these videos too! I’ve a.ways been a real sucker for the SD-40-2 and SD-45’s, in particular the SD-45T’s. Don’t know why. Just love their looks I guess and am a HUGE Steam fan at that. Nothing tops steam!

Was noticing 5401 in the background during the cow catcher video. Saw a DRGW diesel behind you and thought 3011 until I saw the standard EMD cab then the road # and was like oh new acquisition,neat. Second the idea of a 5401 3011 double loco 360.

Wow Hyce ! Thank you so much for this clip. Im building a 1/11 scale version of this locomotive and your video helps me A LOT ! Thank you so much for a close look into the rear of a Tunnel Motor. Btw a 360 video would be super nice ! Cheeers from Germany

Would love 360 video on SD40T-2

Very informative and well explained. I really like your enthusiasm and gestures as you teach your viewers the fine points of the great subjects! All in all, your interest makes us interested😊. Good work, my friend and many thanks❤

Mark, YES please continue the tour with a 360 video on the CRRM’s newest acquisition 5401! I know very little about diesel choo choos so this latest video furthered my understanding of them. Love that the original paint scheme survives. What a gigantic locomotive for sure. The huge cold air intake was ultra OMG, almost like a screened in porch. I was thinking a few lounge chairs and could provide a nice shady area during the hot summer months 😂. Opening up the compartments and pointing out important components and what they do was not only fun to see but such great learning moments as you discussed the details. And as you say, Mark, it’s so all about the details! Congratulations to the fab CRRM on their latest rolling stock collection acquisition. And most importantly many thanks Professor for yet another excellent learning video and as always cheers to you!

Former EMD mechanic here, once we got a call from a customer saying the engine shut down and wouldn't start back up. And they said it wouldn't stop beeping for hours and just couldnt figure it out. We went out there to a geep and turns out the only problem was the governor button was out. Pushed it back in and problem solved 😂 topped off the water and the oil to make sure and checked its vitals. Everything was all good!

Would love to see 5401 in a Loco 360 piece. And considering it’s recent retirement, run again. (As Jeremy Clarkson would say “how hard could it be??”)

Here in Vermont, we have one of Southern Pacific's SD40T-2s still running. NECR 3317, built as SP 8256 in April of 1980 is still used almost daily across the NECR system. sadly NECR Repainted it to the standard boring orange and black G&W scheme, but it sure is fun seeing such a unique engine here in the far northeast. I am hoping for it to stay for a long time, however it sounds like NECR will be receving GE -9 power sometime this winter and either selling or scrapping a lot of the classic EMD fleet including former a DMIR SD9 (NECR 1750)

I'm a recent subscriber to your channel, loving all the info you share. A trip to the museum is on my list, it is only 7 hour drive away after all lol. A 360 video would be nice, watched the 360 video not long ago on the 5629. You mentioned one of it's sisters on display in Wyoming, the 5633. It's at the Douglas, WY railroad museum. Great fo have seen a sister loco on several occasions thats not far from me. Thanks for all you do Hyce.

If you can find the book,,very rare, titled the "Mack Railroad" the Gilsonite Route. It describes special built Baldwin locies articulated in the middle to make the sharp curves up Baxter Pass in Mack Colorado to Bonanza Utah to haul Gilsonite back to Colorado. When it shut down both Locies disappeared. One was found some 20 years alter in Honduras. From what I understand it is still there, on a side track covered with Jungle groth. Only two of the exotic engines were made.

Great video and very informative.

Please do a locomotive 360 on the tunnel motor and maybe 683 too

Dang was gonna do a vid on tunnel motors but this is better than i could have done. Especially since you could get to one on hand lol great vid mark

very cool! sd40s are one of my favorite locomotives!

Awesome video. Thanks for explaining the differences.

I LOVE THESE ENGINES IN TRAINZ 2019!!! ❤❤❤. Although it’s the southern pacific version but it’s still really cool. Thanks Hyce for featuring this beautiful engine in this video. Great video. 👍

I love watching your videos and as a helper in a maintenance shop the standard SD40-2 is 68ft 10in, where the SD40T-2 is 70ft 8in the Locomotive is slightly longer to accommodate for the rear tunnel radiator

You know darn well that we'll watch a Locomotive 360 of literally everything, even those railmotors, a hand-cart, heck, a tool dolly you left across the tracks in the shop. (Save that film for 1st April.)

Once again, I really enjoy this level of nerdy detail that I could never find in books when I was growing up. More nerdy detail videos!

Oh yes, one of my favorite locomotives. Not that many around anymore, but a few places like the NYS&W still have some in service (in a magnificent paint scheme as well)

Great job !!!

a 45min video about some interesting technical piece of history, i dont see the issue hyce :-D

Thank you. Learned something today.

I just rode the Amtrak California Zephyr through the Moffatt tunnel last week on my way home to California. 10 minutes for the 6 miles and no moving between cars through the tunnel. I didn't notice any particular diesel fumes either. The section between Denver and Glenwood Springs or Grand Junction is a great trip for the exceptional scenery.

I’ve always heard that the point of the tunnel motors wasn’t really to keep cool inside the tunnel, because pretty much all air in the tunnel gets hot after a little bit. But rather it was to cool down faster when it was outside the tunnel, so that it’s ready for the next tunnel.

Thanks for another great video. Stuff only train geeks would love - me being one of them. 🚂😁

Oh gee, I love your 'train of thought'.

One of my former locos was a GP15-1, the baby tunnels. I've really liked the cooling system

I grew up near a SP yard and got to see tunnel motors as a kid, Locomotive 360 on the tunnel motor, yes please! I'm also curious about the No. 50 switcher, I would like to see a video about it one of these days. Thanks for another great video.

That was one really cool video about a very unique diesel locomotive. The SD40T-2 is the most unique diesel locomotive I've ever heard of.

Really interesting. Nice video.

Thanks Hyce, YES on the loco 360, the Tunnel motors were my favorite back in the 80’s.

Great video!

Thank you, very informative.

this was awesome

Intresting to see the details of the cooling system and the differences between tunnel motors and regular SD40-2s, tahnks :)

The tunnel motor is a classic. SP, D&RGW and Cotton Belt ordered this model. There's another one known as SD45T-2 only ordered by Southern Pacific and Cotton Belt. #5401 is one of two preserved SD40T-2s, the other one being #5371 at Utah State Railway Museum. Im glad they saved some SD40T-2s and an SD45T-2 for preservation.

Neat! I didn't know this was a thing!