Western Railroad Discussion > Class Unit UP 4900

Same place as NS 8798 locaton  UP 4900 leads UP 4684 and another Class unit 8399 South on a Southbound Z train at Corsicana Texas

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Looks to be a SD 60m or 70m

Posted from Android

UP SD70M's started with 4000 (which would be considered the "class unit"). With add on orders and the SP ones it ranges from something like 38xx or 39xx to 51xx iirc. The "newest ones" are in the 5xxx series right in front of the GE's.

Rivet counters can provide more detail.

Posted from iPhone

MW810 Wrote:
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> UP SD70M's started with 4000 (which would be
> considered the "class unit"). With add on orders
> and the SP ones it ranges from something like 38xx
> or 39xx to 51xx iirc. The "newest ones" are in the
> 5xxx series right in front of the GE's.
>
> Rivet counters can provide more detail.
>
> Posted from iPhone

They start somewhere in the 3700s and go into the 5200s.
They've wrecked and scrapped about a dozen, but they still
have over 1,400.

The 25 former SPs are the 3999 thru the 3973, minus the 3985.
G

MW810 Wrote:
-------------------------------------------------------
> UP SD70M's started with 4000 (which would be
> considered the "class unit"). With add on orders
> and the SP ones it ranges from something like 38xx
> or 39xx to 51xx iirc. The "newest ones" are in the
> 5xxx series right in front of the GE's.
>
> Rivet counters can provide more detail.
>
> Posted from iPhone

Ex-SP SD70Ms were ordered in the year of the announced merger (1996, numbered UP 3974 to UP 3999 now), but I believe UP 4000 (which I've seen a handful of times) is the class unit, the first unit ordered by the railroad, it seems, based on Don Strack's UtahRails.net web site. Later orders are scattered around, numbers-wise, and grouped as you mentioned.

FYI, there is a handful of SD70Ms in 52xx numbering (yes, caught a few leading).

Thanks For clarfying I was under the impression that class units  were like 4000-4099 4200-4299 and so forth.

Jerry

Many older UP SD70M's have been in storage.   Still great seeing these 15+ year old units on the front lines.   In a few more years, they are bound to start thinning.

      The 'class unit' is considered to be the first one of the entire group. In the Union Pacific case it would be the 4000.

All or the last of the 52xx SD70's were the last built. They feature a computer display with side console with analog air guages - and an old school air brake setup - vs desktop constrols and air brake setup of the same era.

My guess is that these were an add on to someone else's order, but no idea.

The SP SD70's may have been ordered around the time of the merger, but were ordered with SP options. They cannot lead in cab signal territory.

UP streamlined these to UP standards as much as they could removing the nicer seats, dual head radios, etc to conform to the rest of the fleet.

> FYI, there is a handful of SD70Ms in 52xx
> numbering (yes, caught a few leading).

>
> Ex-SP SD70Ms were ordered in the year of the
> announced merger (1996, numbered UP 3974 to UP
> 3999 now), but I believe UP 4000 (which I've seen
> a handful of times) is the class unit, the first
> unit ordered by the railroad, it seems, based on
> Don Strack's UtahRails.net web site. Later orders
> are scattered around, numbers-wise, and grouped as
> you mentioned.
>

the SP SD70M's were ordered in 1993 and delivered in the summer of 1994, long before the merger. It was the positive experience with the 25 former SP SD70M's that inspired UP to place its initial 1000 unit SD70M order to replace worn out power acquired in the SP and CNW takeovers.

Bryan Jones
Brooks, KY
Bryan's Train Photos