NS DDM1

[Isahh]

He fast with it dayum!

[Sjoerd]

Luckily, I can take over a few parts from earlier build trains...

[BR Bad]

It looks hella nice! i still have some parts of the DDM-1 so if any pictures or references are needed lmk!

[brozma]

The endcar had a lower roof above the rear end; this was to provide space for a pantograph. This pantograph was not ment to power the train for driving, but to keep the systems on the train functional if the locomotive was uncoupled. Back then, the Dutch railways also ran freight trains (this is now done by other rail operators), and they wanted to park the DDM1 trains at night, and have the locomotives run freight trains until the next morning, when the locomotives could be returned to passenger service. While the locomotive was away, the pantograph on the endcar of the DDM1 train could be used to keep the onboard systems going (like the heating, and the compressors for the airbrakes). I do not know how common this was actually done.
Later series of these doubledeckers did have the lower roof on the endcars, but no pantograph installed. So the practice of uncoupling the locomotives for other duties must not have been very operationally succesfull.

TBH that sounds very unusual, I mean I don't think there are passenger carriages, which uses panto to only power it's internal compartments and not for propulsion, anywhere else around the World. Also that method of power supply has a huge disadvantage. What if the carriage is parked somewhere without catenary? The panto will be completely useless in that case.

And for example from another country, in Czechia, the heating and power supply of the passenger carriages were never solved by installing a panto on the car's roof. It was solved completely differently.

Heating:
In the early days of railways on Czech (that time Czechoslovakian) soil, the closed solid fuel stoves were used to heat up the carriages. But this method was quickly replaced by the other methods, due to high probability to accidentally cause carriage fire, and if the chimney was defective, the smoke from the closed fire could leak into the carriage's interior.

The 2nd commonly spread method of heating was steam heating, which was commonly used during steam locomotive era. The steam heating used a surplus ammount of steam from the steam loco, which was forced through the series of radiators inside the carriage, the heat from the overheated steam (the steam, which has temperature above 200 °C) was dissipated into the air inside the carriage, heating it up. the steam was then expelled out at the rear of the last carriage. Nowadays, it's only used on historical cars, used with steam locos during "retro rides." The huge disadvantage of steam heating is neccesity of the steam loco to be coupled to carriages, this disadvantage was at first resolved by either coupling a heating car to the train, or using a steam generator in some of the older diesel locos

The 3rd and still used heating method is a diesel-heater, which heats up the carriage by burning the heating oil and heating up the air flowing through the heat exchanger, which is then vented inside the carriage. This method is usualy used on the carriages, which are usually coupled behind the older DMUs and used as a add-on cars. But sometimes they're coupled behind a loco as well.
Notable examples of DMU add-on cars with diesel heaters:
1st: Btax class passenger cars, which are usualy coupled to ČD class 810 DMU
2nd: Bdtn class passenger cars, which are usualy coupled to ČD class 854 DMU
The huge advantage of diesel heating is independent operation. The heating can work even, if there's no loco/DMU coupled to the cars. The only disadvange is a huge fire hazard in case, if the heating oil tank springs a leak during derailment or accident.

The passenger saloon of the DMU is usually heated up by the heating system, identical to the heating system in the regular road car.

The 4th and final heating method also used until nowadays, is electric heating. This method of heating is widely spread and used on most of the carriages and even in EMUs. It works identically to the ceramic heater, but it's connected to ventilation system, which spreads the heat evenly. The power supply for electric heating is either a electric loco, which has additional circuitry, powering the heating system, or a diesel loco, equipped with a secondary generator, which powers the heating as well. The huge advantage of electric heating is compatibility between cars and locos. Any electric loco with additional circuitry or diesel loco with secondary generator can heat up any carriage with electric heating. The only disadvantages are
1st: A need for the loco to be coupled to carriages and the said loco must be equipped with additional circuitry (in case of the electric loco) or a secondary generator (in case of the diesel loco).
2nd: In case of the diesel loco, when the secondary generator is active, the diesel loco doesn't accelerate at 100% of it's maximum power. Also most of the diesel locos revs up their engine a bit, when secondary generator is active, which can be quite noisy.

Power supply:
The older carriages and DMU add-on carriages are powered by axle-mounted generator. An alternator, which is either directly mounted to axle, or mechanically connected to the axle. As the car is moving, the spinning axle spins the generator, making electricity for recharching the battery and powering the utilities (lights, announcement system, etc). It's not used to heat up the car's interior, the other methods mentioned above are used for it. The advantage of axle-mounted generator is independent operation. It can work regardless of the loco/DMU coupled to the carriage. The disadvantage is the fact, if the carriage stands still, the generator isn't working and standing still for too long may deplete the battery.

The newer carriages uses power supply called "Central power supply" (In Czech "Centrální zdroj energie"), it works by taking the power from the electric heating circuitry and using it to charge the battery and to power the utilities. It doesn't interfere with heating in any way, althought it poses an extra load for the loco.

[Sjoerd]

TBH that sounds very unusual, I mean I don't think there are passenger carriages, which uses panto to only power it's internal compartments and not for propulsion, anywhere else around the World.

Here are pictures of the pantograph:
https://www.martijnhaman.nl/afbeeldinge ... %20tn2.jpg
https://www.folst.nl/dubbldek/dd_1.jpg

Also that method of power supply has a huge disadvantage. What if the carriage is parked somewhere without catenary? The panto will be completely useless in that case.

That doesn't happen; these carriages are used in combination with an electric locomotive. Therefore, they will only be parked at electrified sidings.
Only when they are not needed for an extended period of time, you might put them on a non-elektrified siding....(for which you need a diesel shunting locomotive to make that happen) in which case keeping the heating and aircompressor running is not required.

[TreinspotterDeamyen]

Perhaps the mDDM will be done as a next project.

DDZ

[Sjoerd]

Let's do an activity test;

[AlistairCowell]

is it me? I noticed the carriages had the destination sings, DDM-1 did not have those DDM2/3 did

The later batches (DDM2/3, I think they are actually DD-AR) also have BSI couplings as wells as destination signs, which DDM-1 doesn't.

[RotterdamMetroLover]

DDM2/3 are indeed called DDAR

[NJTFAN1235!]

DDM2/3 are indeed called DDAR

DDAR?