There is a specific ritual to viewing 35mm slides that digital photography will never quite replicate. It’s the mechanical thwack of the carousel, the smell of a warm projector lamp, and that momentary darkness before a world of vibrant, saturated colour washes over the room.
Today, I’m pulling a particularly sharp frame from my collection: Aigle-Ollon-Monthey-Champéry (AOMC) Unit 591, captured in the crisp Alpine light of Aigle, Switzerland. This image represents more than just a piece of rolling stock; it captures a pivotal era in Swiss mountain railroading where heritage charm met modern efficiency.
The Subject: AOMC BDeh 4/4 591
The train in the slide is a two-car electric multiple unit (EMU), specifically a BDeh 4/4. For those unfamiliar with Swiss railway designations, the "h" is the crucial bit—it stands for Heubele (rack), indicating that this train is equipped with cogwheels to tackle the punishingly steep gradients on the climb to Champéry.
When I took this shot, Unit 591 was the face of the line. Dressed in its distinctive red and white livery with the stylized mountain peaks along the roofline, it looked every bit the modern mountain climber. These units were built by ACM (Ateliers de constructions mécaniques de Vevey) with electrical components by ABB.
What strikes me most looking at this slide today is the cleanliness of the design. The large, wraparound windscreens and the bold "591" numbering give it a friendly yet industrial aesthetic. It was designed to provide tourists with panoramic views of the Valais Alps while serving as a reliable lifeline for the locals living in the villages scattered along the mountainside.
The Setting: Aigle Station
The location is the forecourt of Aigle station. For a rail enthusiast, Aigle is a sort of "grand central" for narrow-gauge lines. While the Swiss Federal Railways (SBB) main line thunders through on the valley floor, Aigle serves as the terminus for three distinct narrow-gauge adventures:
The AL (Aigle-Leysin)
The ASD (Aigle-Sépey-Diablerets)
The AOMC (Aigle-Ollon-Monthey-Champéry)
In the slide, you can see the unique "street running" aspect of the AOMC. Unlike the heavy rail lines tucked away behind fences, these trains often share the asphalt with cars and pedestrians for the first few kilometres. There’s something inherently romantic about a high-tech mountain train waiting patiently next to a sidewalk, its pantograph reaching up into a web of overhead wires that crisscross the blue Swiss sky.
The 35mm Aesthetic
Let’s talk about the medium. This was shot on high-quality 35mm slide film, and the scan reveals why many of us still cling to our "analog" archives. Look at the way the red paint pops against the white bodywork—there is a depth and "glow" to the colours that digital sensors often struggle to interpret without heavy post-processing.
The shadows are deep but retain detail, and the highlights on the chrome and glass don't "clip" harshly. Even the subtle textures of the cobblestones in the foreground and the architectural details of the Swiss building in the background are rendered with a tactile quality. Looking at this scan, you can almost feel the dry, cool mountain air.
Why This Unit Matters
Unit 591 and its siblings represented a transition for the TPC (Transports Publics du Chablais). Before these units arrived in the late 80s and early 90s, the line relied on much older, wooden-framed or early steel carriages that, while charming, couldn't handle the increasing demands of ski tourism.
The 591 brought air suspension, better heating, and significantly faster climb times. It bridged the gap between the "vintage" era of rail travel and the ultra-modern, low-floor Stadler trains that dominate the region today. In many ways, this slide captures the AOMC in its "Golden Age" of modernization.
Memories of the Line
If you ever have the chance to ride the AOMC, take it. Leaving Aigle, the train winds through vineyards that produce some of Switzerland’s finest white wines. It then crosses the Rhône river before beginning its dramatic ascent.
The "rack" section is where the magic happens. You hear the mechanical clatter as the cogwheels engage the center rail, and suddenly, the train is tilted at an angle that feels impossible. Looking out those big windows, you see the valley floor drop away, and the jagged peaks of the Dents du Midi come into view. Unit 591 was the perfect vessel for that experience.
Final Thoughts
This slide is a prized part of my collection because it isn't just a photo of a train; it’s a timestamp of Swiss precision and Alpine beauty. Every time I scan another slide from this trip, I’m reminded of why the 35mm format remains the gold standard for many of us. It preserves a moment in a way that feels permanent.
The AOMC has changed since this photo was taken—liveries have been updated, and newer stock has been introduced—but in this 2x2 inch piece of film, Unit 591 is still shiny, new, and ready to climb.
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