As I have said before I have a passion for the large locomotives of the Union Pacific Railroad and in this post I will share with you the first stages of my designs for Alco’s massive Century 855.

This locomotive, or rather set of three locomotives, were Alco’s answer to UP request for a 15000 horsepower set of locomotives to replace their Gas Turbines.  The Gas Turbines were becoming increasing more expensive to run.  15000 horsepower could have been obtained by simply running six 2500 horsepower locomotives together such as GP35s.  However UP were concerned that the running costs of six locomotives would be considerably higher than say three much larger locomotives producing the same overall power.  So UP approached three of the main locomotive builders of the time; Alco,  Electro-Motive Division (EMD) and General Electric (GE).

All three companies produced big locomotives for UP to trial that shared two main principles; they were all twin-engine units riding on a single chassis and they all had eight powered axles.

EMD’s offering as pictured below was the DD35, pre runner to the DD35A & DD40AX.  The DD35 was effectively two GP35 bodies joined together riding on a pair of four axle trucks. It had no cab and was used as a booster unit.  EMD’s demonstrator set consisted of two 2500 horsepower GP35 locomotives and two 5000 horsepower  DD35 boosters. Together they gave the 15000 horsepower UP were looking for.  This is a model I have already produced for N Scale and you can find it here.

GE’s offering was the U50, as shown below paired with a EMD DD35.  This locomotive was built up from a pair of U25B locomotives on a singe chassis.  The chassis and trucks for the U50 came from retired 4500 Gas Turbines that the UP had traded back to GE.  So, as with the 4500 Gas Turbines, the U50 rode on four two axle trucks grouped in pairs and connected by span bolsters.  Unlike the DD35 these had cabs and could be used as single 5000 horsepower locomotives or in a set of three to meet UP’s requirement.  The U50 below is a production model made by Con-Cor.

Alco’s answer to UPs request was the C-855.  The C stands for Century and this locomotive was part of their Century series of locomotive that covered everything from small switching locomotives to these massive road engines.  The 855 refers to the numbered powered axles, eight in this case, and the horsepower.  The pair of sixteen cylinder Alco 251C diesel engines put out 5500 horsepower and in 1964 this made the C-855 the most powerful locomotive for its time.

Here is a link to a picture of UP number 61 taken by Chris Zygmunt in 1967 somewhere in Wyoming.  (Picture courtesy of www.railpictures.net)

As with the U50 UP traded in retired 4500 Gas turbines but Alco only used the trucks for their new locomotive, the chassis was a totally new design.  Alco built three locomotive as their demonstrator set consisting of a pair of A units with cabs and one cabless B unit.  Together the set produced a formidable 16500 horsepower and had potential for being the dominant locomotive.  But sadly due to poor performance UP did not order any more.  The original set of three stayed in general service based out of North Platte, Nebraska for nine years before being scrapped in February 1972.

Here is another link to a photo showing the set of three from Rick C’s collection.(Picture courtesy of http://www.rrpicturearchives.net)

These locomotives are considered by many to be very ugly with their lumps and bumps and I am inclined to agree.  However I think that they are so ugly they become interesting.  These have never been mass-produced by a mainstream manufacturer in N Scale, probably because only three were ever made and they didn’t last that long.

The first thing I needed to sort out for this locomotive was the power chassis and for this I am going to use Con-Cor’s 4500 Gas Turbine/U50 power chassis as pictured below.  This made sense as the trucks are the same.

The downside to using this chassis is it’s too short.  As Alco only reused the 4500 Gas Turbine trucks and not the chassis they repositioned the trucks further apart.  As this model is N Scale I did look at whether a bit of modeler’s license would be used, if the difference was small it may not be noticed.  But as I started taking measurements it soon became clear that there was a fairly big difference and I wanted to get the locomotive right.  To overcome this I will be 3D printing a metal extension piece to fit into the middle of the chassis.  This will push the trucks further apart but keep the motor in the middle of the locomotive.  I will cover that in a later post but you can read about how I drew the chassis ready for this in an earlier post which you can find here.

With the chassis decided upon and the modifications underway it was time to turn to the main body shell.  Working from drawings and photos that I have been able to gather I have drawn the bulk of the main locomotive.  Below are some work-in-progress shots of the 3D modeled shell.

There is still a lot of detail to add and finish off before it is ready to go for a test print but I am hopeful that this will happen by the end of February.  As with my previous locomotive models the C-855 will have brass Additions which will include the handrails and roof walks as well as several other small details.  The large sandboxs on the sides will also be separate parts to make painting an easier job.  The shells for both the A and B unit will be available and both will fit onto an extended Con-Cor 4500 Gas Turbine/U50 chassis.  I will also be making a dummy chassis available for each unit.

In next week’s post I will share with you the design for extending the chassis using 3D printed stainless steel.