UP DD35 DD40X

[Anonymous]

RR-FALLENFLAGS.ORG has some good pic's of these UNION PACIFIC DD35 A-B units they need something like the DD35-B these days or a more up to date version of a DD40X A or B just for power think of the newer locos they could send out on trains in stead of 3-4 AC44 or SD70ace's they could line up 1 DD40 A 1-2 DD35-40 B units and still have more power [8D]

[chad thomas]

The DDA40X was basicly 2 GP40s on one common frame. The problem is when one engine (so to speak) goes down and has to be shopped, the other goes with it. Plus there is the loss of flexability. It's even worse for the B units.

The true SD90MACs and AC6000s are more powerfull then the DD35s by 1000hp and just shy of the DDA40X by 600hp.

I have never seed a DD in road service. I wish I had. I belive all the 35s went to scrap but fortunatly there are many DDA40Xs preserved around the country. And UP still rosters the 6936, although it only has one engine in it now.

[jchnhtfd]

This has probably been discussed before -- in fact I'm sure it has. In general unless you have a division on your line where virtually all of the trains require a lot of power, you gain tremendously in flexibility and reliability by using two or more engines in multiple, rather than one great big one. This wasn't true in the days of steam, for a variety of reasons,which is why you did see some really big engines.

It is very interesting to study the shift in thinking from the steam era through the transition era to now; the first diesels were often sold in more or less permanently coupled sets of two to four, but it didn't take long for the trainmasters to figure out that they could gain a lot by splitting them up.

The economic/reliability balance between multiple units and big power is a rather fine balance!

[Anonymous]

In addition to permanently coupled sets, E units were double-engine locos and UP had a lot of them, so apparently UP wasn't too worried about inflexibility when they ordered the DD units. The later ones were ordered with high speed gearing for use on livestock specials and other fast freight trains. A book I have on the LA&SL has quite a few pictures of these trains and some of them ran across Nevada with 8 or more early GPs and SDs. During the steam era they ran with double headeded Challengers and one picture shows 2 complete A-B-B-A sets of FAs, or about 12,000 hp.

[Anonymous]

well they are a sight ive been on 6936 while it was taken from cheyene to N little rock for a pass special it then went to st louis & chicago they also have one set out on display at the west end of jenks yd in NLR ark but your right
its to much work when you gotta fix 2 motors on the same loco [8D]

[chad thomas]

Another reason the DDs were less favorable with shop forces is the height of the walkways were higher and did not line up with the raised shop floors.