Introduction: A 1920x290 bar LCD fits the long, low space above train doors, but its unusual cut ratio changes how route text, icons, and map lines have to be laid out.
Anyone who has stood in a train car waiting for the doors to open knows the moment. The chime sounds, the head tilts up, and the eyes hunt for the next station, the transfer line, and which side the doors will open on. That glance lasts two or three seconds. The display above the door has to answer those questions in that window, from a standing position, sometimes three meters away, sometimes right underneath. A standard 16:9 monitor fights that space; a stretched bar does not. What follows is a walk through the ratio, the pixel grid, and the viewing geometry that decide whether a door-top strip actually reads well.
Above a train door, the available surface is a wide, shallow band — roughly the width of the doorway and only as tall as the panel trim allows. That geometry, not fashion, is what pushes rail interiors toward a stretched bar LCD instead of a standard monitor. Once you look at what the strip has to do, four constraints show up together.
This is why the bar LCD format exists at all. A 36.6-inch panel with a 919.296 × 138.852 mm active area and a 1920 × 290 resolution gives a window of roughly 6.6:1 — wide enough to carry a route strip, shallow enough to sit above the door without protruding into the opening. The shape is a fit to the car rather than a styling choice, and it is the reason a rail vehicle display manufacturer treats bar formats as a product family of their own rather than a trimmed-down version of a standard screen.
The first thing to notice is the pixel grid. 1920 × 290 means 1,920 pixels across and 290 pixels down. Spread across a 919.296 × 138.852 mm active area, each pixel measures about 0.479 mm on both axes, which works out to roughly 53 pixels per inch along the long side. Those pixels are square, and on a stretched panel that is not a given. Some wide formats pair a long diagonal with non-square pixels, so a circle drawn at 1:1 comes out oval and a typeface loses the proportions it was designed with. Square pixels keep station dots round, keep arrows straight, and keep a station name looking like a station name. The second thing is the vertical budget. With 290 pixels of height, the panel cannot simply shrink a widescreen layout and hope for the best. A workable route strip divides that height into bands: a line for the current or next station, a smaller line for the transfer or terminus, and a map band underneath. Route lines run as horizontal strokes a few pixels thick, with antialiasing on the diagonal connectors where one line merges into another. Icons are typically drawn between 24 and 32 pixels, which is enough for a clear door-side arrow or a wheelchair symbol but not enough for a small logo with embedded lettering. The width works in the opposite direction. Because 1,920 pixels spread sideways, a dynamic map display can carry four to six separate text zones at once and still show the next station, the following stops, and the platform side in one glance. Resolution is not the whole story, though. Cabin lighting, panel reflections, and viewing angle all shape what a passenger actually sees; the ratio and the pixel grid decide whether the content has room to exist in the first place.
The viewing distance is short by signage standards but long by screen standards. A passenger standing at the door reads from about one meter; someone seated across the aisle reads from roughly three. At three meters, a single 0.479 mm pixel subtends about half an arcminute — below the one-arcminute threshold that defines normal visual acuity. No sensible layout depends on a one-pixel stroke. Practical route strips build letters from two- or three-pixel strokes and set station names with cap heights in the region of 30 to 45 pixels, which comes out at roughly 15 to 22 mm of physical height. A name at that size reads comfortably from three meters and stays crisp at one meter, where the panel fills far more of the viewer's field of view. Movement adds a second constraint. A train is rarely still while the doors are open; braking and acceleration shift a standing passenger's balance, and the useful reading window is often just the few seconds between the door chime and the moment the doors close. Layouts that work at a desk — dense paragraphs, tight line spacing, long lists of stops — lose that fight. Route strips do better with large station names, generous spacing between lines, and a diagram that shows only the next few stops plus the terminus. Passengers also look up at the panel from a range of vertical angles, so the most important line belongs near the vertical center of the strip rather than at the very top or the very bottom edge, where the viewing angle is steepest.
A 1920 × 290 resolution is not a headline number chosen for marketing. It is the outcome of matching a display to one specific piece of a train car. The shape fits the shallow band above a door. Square pixels keep type, arrows, and station dots in their intended proportions. The 1,920-pixel width leaves room for several information zones side by side, while the 290-pixel height sets a hard vertical budget that forces disciplined layout. Viewing distance then decides how large station names and icons have to be drawn. Readability on a door-top strip comes from all of these working together, with the resolution acting as the frame that makes the rest possible. Anyone comparing bar panels for a rail interior will get further by asking how a panel handles text at a distance than by comparing pixel counts alone.
A：Because the space above a door is wide and shallow, not square. A 16:9 screen with the same 36.6-inch diagonal would stand roughly 46 cm tall and would not fit the door header without protruding into the doorway. The 6.6:1 cut keeps the diagonal length while flattening the panel into a strip, and the 1920 × 290 grid keeps pixels square so text and route lines stay in proportion.
A：It uses horizontal spread instead of vertical height. Station names, the line diagram, transfer hints, and door-side cues sit side by side across 1,920 pixels, so a passenger standing at the door and a passenger seated across the aisle both scan the same left-to-right band. Station names set with cap heights around 30 to 45 pixels hold up at roughly three meters, and the shallow panel keeps the change in viewing angle small as people move around the vestibule.
A：The panel either protrudes below the header or forces the content into a letterboxed band, which wastes most of the glass area. Designers then scale text down to fit the unused width, so station names shrink and become hard to read from a few meters away. A route diagram has to wrap or compress into a short segment, breaking the left-to-right reading pattern passengers expect, and the surplus vertical area adds nothing to the journey information.
International Committee for Display Metrology
