They are NOT supercharged. They have a scavenging blower. The blower is not intended to provide higher then atmospheric pressure to the cylinder. It is required to blow out the spent combustion gases and trade them for fresh air. Later, in the 50's and 60's and beyond, those same blowers were modified to fit on gasoline engines where they did in fact become superchargers.

You count your rivets, I count mine ;)

Thought I would post a photo of the Model 40 at North Judson. Had a young member who took an interest in the unit a number of years ago, and he got one of the Detroit's fired up and moved it up and down the track until he was told to abandon the effort because he was making too much smoke. The unit is now strictly a display at Hoosier Valley.

Les

The Walkersville Southern tourist operation in Maryland has one of these beasties, and at least the last time I was there, it was running.

Definitely Detroit/GM 6-71s under each hood.

Model 40 Operator's Manual shows weight ready for service as 81,000 lbs.

EMD rates total HP as 300. Possibly because lower than max RPM (to match the same generator as used on SW1) reduced output accordingly.

How many of the 11 built remain intact today?

The GMDH-3 resides at the Southern Michigan Railroad Society in Clinton, Michigan to be exact. Currently stored out of service but accessible in our yard.

Am I interpreting this correctly, even though you have 2 prime movers, there is no way to disconnect one engine? So you really running a split block 12-71... I wonder was this done to balance the axle weight or because the 6 cylinder engines were more common?

Rich C.

Both engines are mechanically connected to the generator. If only one is running, the other is "going along for the ride."

Perhaps EMD's designers chose the 6-71 for its commonality and were influenced by the many centercab designs by various other builders.

Here’s the updated photo of 2284:

I can confirm that the Walkersville crew does have one, and as of three years ago, at least, it was running. How do I know?

https://youtu.be/yuIxZ6dfiDc

It is Walkersville primary engine on our regular trains. It is great little engine... when it's not Raining.

Here's something amazing to me--of the 11 units built, 8 are still around, some still in commercial service.

And if I counted right, six of the eight are accounted for this this thread.

https://en.wikipedia.org/wiki/EMD_Model_40

The ex-AMF unit in York has the hoods and access panels open for inspection, a well as the cab open with stairs into it. Peering under the cab deck I could see the single generator with the two shafts into it....nah, couldn't be. I'm missing something here.... they couldn't have done it that way...

Huh!

Correction on my previous post, the TRAINS salute to the EMD Model 40 was in the September '72 issue (EMD special) and the article was "Occasional Violations" with the AMF Big Bill unit getting a two-page spread. It was based on the violation of EMD's standard principle - standardization - and how nothing before, after, or since was quite like the EMD 40.

I had a nice visit yesterday with (and how many people can say this?) an EMD Model 40 at Professional Locomotive Services in East Chicago, IN. Thank you to the staff at PLS for letting us see this survivor that they have restored to museum quality! Note the wood trim in the cab and there are roller bearings behind those friction bearing covers! Order number E574-1 was built in 8-22-1942 with serial number 2284 for the US Army # 7952, it was sold to Acme Newport Steel (Newport, KY) NPTX #1, Professional Loco services rescued this unit that was very close to being scrapped. The unit was trucked to East Chicago and thoroughly rebuilt by PLS to better than new condition. The "critter" now serves as PLS shop switcher, resplendent in Ferrari Red and moving much larger units like SD60M's or AC4400's with ease! Some time back I thought that I read that the builder's plate was being held by someone until the unit was finished and that they wanted to give the plate back. If anyone knows about this, PLS would love to get the plate mounted back on the 300...if you look at my pictures, you can see the six mounting holes in the frame below the cab!

The GM Detroit 71-series was developed in the late 1930's and is similar in operation to the EMC 567 series: 2-stroke uniflow engines with admission thru ports at the bottom of the cylinder and exhaust through poppet valves at the top. The Roots blower supplies air which has to be enough above atmospheric to push the exhaust out the top. Until 1957 they were inline only and the 6 cylinder 671 was the biggest engine in the series. To get more power GM paired 671's and geared them together which is what's in the Model 40. Australia's Victorian Railways EMC gas-electric motor cars were reengined with paired 671's as well.

Phil Mulligan

Here's one of John's photos from his visit to PLS.

Les