DF7C Class Diesel-electric Co-Co
The DF7C is a six-axle diesel electric locomotive, primarily used for shunting and industrial work. It has been produced by Beijing 27 Factory and Ziyang Locomotive Works since 1992. 860 units have been manufactured to date with a number of improvements in power output, braking and cab layout. Most of the early DF7C locomotives have a high short hood and and most wear an attractive orange livery with white lining, grey roof and blue/grey under carriage. They are just starting to be replaced in the last few years with new HXN5B diesel locomotives.
Piko's DF7C's represent a huge gap in Chinese models, being a shunter locomotive and a hood unit. They are a plastic shelled body and unusually, manufactured by an well established European company. They are high quality models with good details and all versions are available in DC or DCC with sound.
The first tree DF7C's were sold with a two piece thick cardboard box with the model supported in a sleeved clear plastic clam shell. There is a small bag containing optional type couplers. There are a number of papers including shematic/instruction sheet, warranty information and catalogues for other Piko products. The fourth and so far final run had an upgrade to the outer packaging employing an open cardboard box with cardboard sleeve.
The models are extremely well built and feature some very neat details such as brass air horns, quality metal hand rails, separately applied uncoupling rods, wind visors etc. It is very nice to see Piko went to the trouble of making two sets of tooling to accomodate the variations between particular units. Differences can be seen in the roof, cabs, air-conditioners and air horn placement.
Piko have made these models with a fairly minimalistic approach with much of the detail work. Unlike many new Chinese manufacturers who build their models with literally hundreds upon hundreds of tiny detail parts, much of the details are simply molded onto the body. This isn't to say it's done poorly however and there is always the benefit of not watching your model shed parts gradually over time. Things like pneumatic pipes to the airhorns, builders plates are molded onto the shell. Likewise, the bogies are mostly one whole piece with only the sand boxes and traction boost arms as separate parts. The walkways are very nice and molded with a checkerplate pattern and painted metallic grey. The louver vent details are sharp, but would have been nicer with a little more depth. Some weathering powders would help to accentuate this. Due to the fairly good robustness and lack of separate parts they are very good for younger modellers to learn with.
The paint work is stunning with nice rich colors, representing freshly colored units (the paint tends to fade after some years of service!). The lining is incredibly sharp and characters and numbers are super sharp. Piko have used different fonts for some versions which is a nice touch. Out of all the models Piko have produced they have produced only one version and one decorated version.
The DF7C's are beautiful runners. Pick up is from all wheels which is achieved with very fine copper pickups that press against the inside of the wheels. The pickups are partially exposed, but cleverly disguised with paint. All axles are geared and the loocmotive is a strong puller. The motor and gearbox noise generate very little noise and they run very well through the entire speed range. The motor is helped along with a pair of heavy brass fly wheels which eliminates sudden stopping over slight track imperfections.
Both of my examples are equipped with Piko sound DCC chips. As mine were from the very first batch, I had to install the decoders myself which was a fairly easy process by simply replacing the 21 pin dummy plug with the decoder and feeding the two speaker wires up through the frame and soldering onto the board. The speaker is housed in the fuel tank and it should be inspected regularly as the magnets in the speaker suck up any small metal debris that may be on your track which over time will distort the sound. Note also that these decoders are fairly power hungry compared to other brands. The sound is overall very good.
Lighting is very nice with the DF7C's which includes red and white marker lights front and rear (directional), main headlights (directional), ditch lights, cab light and bogie lights (two above each wheelset).
To access the circuit board and install a DCC chip, there are three screws to remove. The first one is on the roof underneath the panel closest to the long end headlight. To access this, use a small screwdriver, toothpick or similar to pry the panel upwards and it comes away with little force exposing the screw head. The other two screws are directly underneath the cab between the first and second axles. There are another two screws holding the fuel tank to the body which is handy to clean of any metallic debris sucked up by the magnets in the speaker.
The coupler mechanism uses pivoting drawbars with NEM 362 coupler boxes. This presents a challenge for me as I like to use Kadee scale heads which don't have this fitting. For thime being, I have left the stock couplers on these models (black plastic knuckles), however the will accept Kadee 18, 19 or 20 depending on how long you want them (or how sharp your curves are).