When i heard some time ago that Broadway Limited Imports was going to produce AC4 and AC5 cab forwards I started saving my money since the flat-faced AC5 is my favorite of all the cab forward classes. I purchased my model from Trainworld. There were 16 AC5s #4110-4125 built by Baldwin between July and September 1929. #4110 was scrapped at the Sacramento, CA shops in 1953 and the rest of the class was scrapped by mid-1955. With their boiler pressure of 235 psi, tractive effort of ~ 116,000 lbs and 5,640 HP (not sure if this is IHP or drawbar HP), they were only slightly less powerful than classes AC6 through AC12 with the their boiler pressure of 250 lbs, ~124,000 lbs tractive effort and 6,000 HP.
The model has an ABS plastic body with a heavy diecast chassis. It weighs 1 lb. 14 oz. According to the maker it has all-wheel electrical pickup, is 16.25" long over couplers, will operate on rail down to code 70 profile and has a recommended minimum radius of 22". It's equipped with a DC/DCC dual mode decoder with sound and synchronized puffing smoke. Before placing the model on the rails, I removed the Kadee std. head couplers from the loco and tender and replaced them with Kadee "scale" head whisker couplers, #158 medium shank on the tender and #156 long shank on the engine. Although the shorter medium shank coupler will fit on the engine as the glad hand just barely clears the pilot, the glad hand of the adjoining coupler would hit the pilot preventing coupling and not allowing the engine to be used in pusher service. The choice is yours. BTW, with the long shank coupler in place, the length over couplers moves up to 17".
On first starting the locomotive, smoke billowed out from under the smoke box and from the stack. I cannot stand the smell of model smoke as even a small amount of it makes me sick (doesn't smell at all like the real thing) so I shut down and consulted the operators manual learning that by pressing F7 the smoke generator is turned off. Unfortunately, this is not a permanent fix as every time the DCC system is shut down and restarted, the smoke is emitted again. The smoke generator can be permanently shut down by moving a slide switch on the locomotive to the off position. According to the manual, the switch was located behind the smoke box door. However, the smoke box door does not open on the model. I emailed BLI and within the hour received a reply stating that the manual was generic and the switch was actually located under the front of the boiler adjacent to the trailing truck. I turned the locomotive over, found the switch and moved it to the off position. I was really impressed with their rapid response and expressed my appreciation to them in a follow-up email. I do think the smoke off function should be the default condition, however.
The model contains a very comprehensive sound system providing all the sounds inherent to the cab forward. By pressing F8, the level of sound can be adjusted in stages or fully muted. The operating manual, as well as the website contains comprehensive instructions for configuring many of the sound variables. Changing the locomotive address from 0003 to the engine number, 4112, was done with no problems. My Lenz system requires the use of a separate programming track to enter an address and the sound decoder has a capacitor that charges when the programming current is turned on which can interfere with the programming. In some cases I've used a 10 ohm resistor in series with one of the program track wires which prevents current inrush as the capacitor charges but here such an aid wasn't necessary.
The locomotive is an excellent performer and runs extremely smoothly. It easily accomodates my minimum mainline radius of 24" and the #5 turnouts used in my engine terminal (#6 and one #7 curved turnouts on the mainline), and looks good doing it. Momentum effects and acceleration/deceleration delays are just fine without changing the settings of CV 3 and CV 4. It's slow-speed runing is impeccable and it can be brought down to a barely perceptible crawl. With its all-wheel pickup (this includes the pilot trucks also), there is never any hesitation or loss of electrical contact, as one would expect.
The model also exhibits an exceptionally high level of detail for a plastic-bodied machine, closer to what one might expect from a brass model. It looks good to me.
The only thing I don't like about the model is that its running gear is not set up like a real articulated engine which does change its appearance when operating through curves compared with the prototype. Prototype cab forwards had the front engine rigidly affixed to the boiler while the rear engine was free to swing from side to side since it was connected to the front engine by a link. In the case of the model, both front and rear engines pivot from a central point as would be the case with diesel locomotive trucks. This design undoubtedly was chosen to enable this long driving wheelbase locomotive to easily go around fairly sharp model curves no doubt accounting for its ability to traverse those of 22" radius. After studying the design I toyed with the idea of clamping the front engine to the boiler but decided this was unworkable since the rear engine would still pivot rather than be able to swing which might really mess up the locomotive's ability to run on curves and in any case would still not look right. Best to leave well enough alone here. The model may not corner like the prototype but it sure looks good enough in its own right.
I give the model high marks both in terms of performance and appearance and recommend it to anyone wanting a flat-faced cab forward. For those wanting later model cab forwards with the tapered fronts, Intermountain is making the AC8 through AC12 classes so a good variety is currently available.
In the Kalmbach publication "Model Railroad Cyclopedia - Volume 1 Steam Locomotives, Edited by Linn H. Westcott," can be found a number of cab forward photographs. Page 255 contains two excellent builder's photos (both sides) of AC5 #4114 and a photo of AC4 #4100. On pages 256 and 257 can be found an HO scale line drawing of the engine and tender of AC11 #4272, photos of AC7 #4159 engine and tender (both sides), a 3/4 view photo of AC8 #4196, a photo of the flat front of AC4 #4107 and a photo of the tapered front of AC10 #4237.
And just a note to those modelers in DC thinking of purchasing this excellent locomotive: The starting voltage of this locomotive can be reduced from about 9 volts down to around 5. There are instructions on how do do this included with the loco It's a little tricky, but with patience it can be done with little problem. This is really a fine locomotive, and I highly recommend it for all SP steam fans (of which there seem to be quite a few, thankfully).
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!