For a while now, the tagline of my Valley Local project has been "Modeling the New Haven Railroad's Connecticut Valley lines, c. Autumn, 1947 (or 1948, or '49)" and that's done a good job of conveying the layout's locale, as well as the season (neither of which are easily changeable). But the chosen year hasn't been chosen with any real finality... until now.
While I initially focused on Autumn, 1947 (since that was the last year of the "all steam" era in the area - click here for that analysis), it wasn't long before my era "creeped" to as late as 1949. And additional research on these "bookend" years of 1947 & 1949 revealed an interesting fact: the New Haven's all-steam-to-all-diesel transition in the CT Valley was just 3 years: 1947-1949 (thus, my tagline). Here's a synopsis of motive power on the layout in each of those years:
I still plan eventually to host ops sessions focusing on each of these three years since it'll be neat to have my operators know what year it is by what motive power is assigned to their train (oh, and there'll be an era-appropriate calendar on the Bulletin Board as well, in case they don't get the hint...). But recent ops sessions on the Shore Line have prompted a further focus on the Fall of '48. The choice of season is obvious (you can typically scenic your layout for only one season), but here are some of the reasons for the year:
Greater Variety of Motive Power
In the "transition year" of 1948, you still have steam on the Valley and Air Line locals - and by Autumn you can run both K-class 2-6-0s and J-class 2-8-2s on the Valley Local, but diesels (Alco S-2s) are already on the Shore Line locals by 1948 and DL-109s (DER-1s) were already almost 7yrs old.
I can plausibly run my DERS-2b on the Air Line local, as shown here (Alco RS-2s were delivered December 1947).
And I can also plausibly run my DERS-1b on PDX-2 (up the lower end of the Valley line).
Finally, I can even run my Alco PAs on the Shore Line, since they were delivered in September, 1948
Greater Variety of Rolling Stock
During the Steam Era, the New Haven's class NE & NE-4 wood cabooses dominated, followed by all-steel NE-5s starting in 1942. However, I have an NE-6 caboose and those weren't delivered until 1947-48. So I get to use it in Autumn of 1948.
The New Haven's first post-war stainless steel coaches were delivered in 1947-48 and I think the SS parlor cars weren't delivered until 1948.
More-Complete Information
I have a pretty wide breadth of NHRR info, but it turns out that what I have for 1948 is most complete: I have the public and employee timetables, as well as the freight symbol book and package car schedules for that year.
And while I still don't have an engine assignment book for 1947, I do have a report from April 20, 1948 (69 years ago yesterday!) that shows what every single locomotive did on the railroad that day.
John was a well-known and avid New Haven RR modeler and greatly influenced me and many others through his articles in Model Railroader magazine. He was also a firm "steam era" fan and played a big role in getting me to backdate my era from 1952 to 1947. But focusing on Autumn, 1948 has the incidental benefit of bringing John right onto my layout - albeit as an 8 yr old.
Anybody that knew John knows the story of how he got interested in trains, and in the New Haven Railroad in particular. On the Friday of Labor Day weekend 1948 - right before the PAs were delivered - he was on the platform of the Old Saybrook station, right about twilight, when the Advanced Merchants Limited roared by at high speed with 22 heavyweight parlor cars behind double-headed I-4 heavy Pacifics. Recreating that scene will be a fitting tribute to his memory and inspiration.
Most model railroaders focus on a broad era ("the 1950s" or "the steam-to-diesel transition"), but if you're into doing really deep-dive research, you find out pretty quickly that it can be a rabbit hole and the deeper you go, the more you learn (and, the more you realize you don't know). That's not to even mention how expensive it can get, having to equip a layout with multiple years' worth of rolling stock and engines - especially for a railroad like the New Haven, which rostered an impressive variety of equipment over the years.
But that research is just another one of the many fun facets to this great hobby. And choosing one year to focus on primarily (I'm still planning to occasionally go totally crazy and do a 1947 or 1949 session) will get you even deeper into the era - and make the time machine you're trying to create with your modeling as vivid and realistic as it can be.