This year the Norwegian Rauma line celebrates 100 years, and as part of the celebration they put together a triple-headed Nohab train with the Di 3 602 in front.
The NSB Di 3 602 is also known as the Nohab Demonstrator 1 and was delivered to NSB in the atum of 1954, so it's 70 years old this year. (On rental at first, as just Nohab 2246).
The Di 3 602/Demonstrator 1 locomotive is the prototype for the Märklin 37665 and 37686

note that Norway is a small country with a low population, so triple-headed trains are quite rare. (train lengths are limited by primarily single mainlines and limited lengths on the station tracks.)
The Di3 602 + 616 are Co′Co′ and the 642 is a B series (A1A)(A1A) locomotive. The 642 was one of 5 locomotives originally intended for Finland.

A Norwegian article about the Rauma line jubilee (use translator)https://www.jernbanedirektoratet.no/jernbanemagasinet/raumabanen-100-ar/
an old NSB marketing video for the Rauma line https://www.youtube.com/watch?v=i_SX4T48B4U


Since the NOHAB Demonstrator is 70 years old, I have included some more Demonstrator information and pictures for those who are interested:

The Nohab 2246 (Di 3 602) is ready for delivery in 1954, outside the Nohab workshops in Sweden. (Today the Saab car museum is located in the same buildings )


The Nohab 2246 received the demonstrator design in the spring/summer of 1955 before the demonstrator tour. Note the NOHAB-GM text has been added to the stripe on the side.


The demonstrator in Ankara:


After the demonstration tour, the locomotive again received the NSB logo on the front but kept the NOHAB-GM text on the side. Seems like it's to this condition the 602 has been restored, since it has the NOHAB-GM text on the side, but the horn is reversed in the picture.


When NSB bought the Nohab 2246 it was given the Di 3 602 designation, and orders were given to repaint it green with only a big NSB logo on the front. The same paint scheme as the next 5 Di 3 ordered. It was probably painted like this around 1960. It's possible that the white stripe was added a bit later?. Only the 602 and the "Finnish locomotives" did receive a white stripe on a green body, interestingly they are all on a "long" chassis, while the rest of the Di 3's are a bit shorter. The front door was also likely removed at the same time and the later locomotives were delivered without the "nose" door. The side door on the driver's side where also removed later, to improve the conditions for the driver during cold weather.


A German Di 3 602 fan?



The other 2 demonstrators:
The Nohab demonstrator 2, somewhere in Finland: Type: VR KDs1 (Nohab build no 2402). This has an (A1A)(A1A) configuration, similar to the Danish MY locomotives but with a slightly higher maximum speed, 143 kmh. The colour was supposedly the same dark red as the Danish MY locomotives.

After the trials in Finland, the wheels were "squished" together and taken over to Sweden. SJ rented it for a period, and iron ore breaks were fitted. After that, the locomotive was taken over by NSB and given the designation Di 3 643. the 643 is one of 3 locomotives in the Di 3b class.
After it was taken out of service from NSB, it was sent to Trainkos in Kosovo, and later scrapped.

The Nohab demonstrator 3, somewhere in Germany (Nohab build no 2418). The Nohab demonstrator 3, was primarily sent on tour for demonstration in Hungary, but other Western Europe countries were also included.


Nohab build no 2418 and 2419 were also intended for Finland in (A1A)(A1A) configuration, but they were built as Co′Co′ instead after a request from NSB.
the demonstrator 3 was given the designation Di 3 623. Note the former DSB MY 1131 was also painted as Nohab demonstrator around 2008
The Di 3 623 has been taken over by the NOHAB-GM Foundation and is currently under restoration. Since it was damaged in fire it might take some time.
Märklin has a model of Di 3 623 as model no: 3137 and Hamo 8337

NOHAB called this class of locomotives forNOHAB AA16 and it was a licensed production from EMD GM. So the design is basically an American EMD "F7" class modified to fit the European market.
An early drawing, later Nohab lowered the nose to increase the window size.


Specifications: Note that the Di 3b has a higher top speed than listed and also different traction motors. The length of the Di 3a is 18,6m (except 602, 622 and 623)


Starting up the Demonstrator:


The primary source for information here is the Norwegian Book: "NoHAB DI 3 : fra Trollhättan til Nordlandsbanen - en loklegende" by Ståle Næss