Vertical lift module trays do not converge on a single ANSI or ISO standard size, and the engineering reality is that tray width, depth, and payload are sized per OEM model family with the unit height scaled to the facility's clear ceiling. Across the major 2025 to 2026 manufacturer data, common VLM tray widths land at 96 inches, 120 inches, and 144 inches, with a total available range from roughly 3 feet to 21 feet [S2][S3].
Trays deeper than 40 inches are uncommon, and the heaviest documented per-tray payloads reach 2,200 to 3,300 lb, with a documented system capacity near 110 tons on the high end [S1][S2]. Operators sizing a VLM should treat tray dimensions as an OEM-specific selection variable, not a controlled commodity spec, and they should review ceiling height, floor load, and bay window geometry alongside the tray data [S8].
Tray Width: The Primary Sizing Variable
Tray width is the single dimension most VLM OEMs use to define the machine model, because the tray-to-elevator clearance and the structural cross-section both scale with it [S2]. White Systems lists common widths at 96, 120, and 144 inches, with the broader available range running from about 3 ft to 21 ft [S2]. Southwest Solutions Group states that VLM trays span 4 to 12 feet in width along 6-inch increments, a finer granularity that lets integrators tune the footprint to a specific aisle or column grid [S3]. The Modula Lift product family sits at the metric end of the same envelope, with documented tray widths of 1,500 mm to 4,100 mm, roughly 59 to 161 inches [S6]. Across these vendors, the practical selection is dominated by part size, picking window ergonomics, and the structural width the facility floor can accept; the elevator column itself adds several inches to the total machine footprint beyond the nominal tray width [S2].
Tray Depth: The 30 to 48 Inch Working Range
VLM tray depth is a more constrained variable than width, and the dominant North American value sits between 30 and 40 inches for general-purpose SKUs, with deeper 48 inch trays specified where longer parts or larger totes are stored [S2][S5]. White Systems publishes 32 inch and 48 inch as its two standard tray depths, with custom narrow-depth units available for low-ceiling or mezzanine installations [S2]. FCBCO's operations guide corroborates the 30 to 40 inch general-purpose band and notes that the depth is selected to keep product mass near the elevator centerline, which protects lifting dynamics and tray-level deflection [S5]. Modula's slim module documents a 654 mm to 1,257 mm tray depth range, which lines up with the 25.75 to 49.5 inch window, confirming that the 30 to 48 inch band is broadly representative across both imperial and metric product lines [S1][S6].
Unit Height and Vertical Scaling
VLM height is modular and tracks the facility's clear ceiling rather than the tray, with most OEM ranges expressed in small vertical increments so the unit can be tailored to within a few inches of the available envelope [S1][S2][S7]. White Systems offers standard heights from 9.8 to 52 feet in 5.9 inch increments, with custom heights built to the facility ceiling [S2]. Modula's lift and Flexibox lines scale from 10 ft 10 in to 68 ft 11 in, while the Modula Next line caps at 52 ft 10 in, and the slim module is restricted to 7 ft 10 in to 22 ft 11 in for low-clearance sites [S1]. SSI Schaefer's LOGIMAT system scales from 8 feet to 78 feet in 4-inch increments and supports multi-unit linking for taller storage needs, which is the current benchmark for very-high-bay installations [S7]. SSI's 4 inch increment is the tightest published vertical step among major OEMs and gives integrators the most granular ceiling fit [S7].
Per-Tray Payload and System Capacity
Per-tray payload is where the OEM product lines diverge most clearly, and the spread runs from light-duty parts storage to heavy pallet-class loads on dedicated machines [S1][S2]. Modula's lift and pallet lines both advertise 2,200 lb (about 1,000 kg) per-tray capacity, while the Modula Next caps at 1,102 lb, and the Modula Flexibox bins are throughput-rated at up to 180 bins per hour rather than by tray mass [S1]. White Systems publishes 660 lb to 3,300 lb per tray in the standard range with custom trays available for heavier loads, and the system-level maximum reaches 110 tons, the highest documented aggregate capacity in the surveyed data [S2]. For comparison, Modula Lift lists 250 to 1,000 kg per tray on its metric spec sheet, which translates to roughly 551 to 2,205 lb, sitting inside the same envelope as the imperial product lines [S6].
Throughput, Bay Geometry, and Picking Window
Throughput is reported in trays or bins per hour, and the leading OEM values are 140 trays per hour for the Modula lift and up to 180 bins per hour for the Modula Flexibox, with the upper figure applying only to small-item bin picking rather than full-tray retrieval [S1]. Modula's lift offers three bay heights at 27.36, 35.23, and 50.98 inches, which sets the maximum product height a single tray can carry, while the Modula Next lists a picking window size of 3.94 by 2.94 inches minimum to 98.43 by 25.75 inches maximum, defining the operator-facing aperture rather than the tray itself [S1]. These numbers matter alongside tray size because the bay height and picking window jointly determine what is physically presentable from a given tray footprint, and a wide tray with a shallow bay is a mis-specified unit for tall parts. The wider context of VLM installation, floor load, and ceiling height specs is the natural companion read, because the tray data only resolves into a workable spec once the structural envelope is fixed.
OEM Comparison on the Decision Criteria That Matter
Lining up the main OEM families against the four criteria that drive a procurement decision: White Systems, Modula Lift, Modula Next, and SSI LOGIMAT differ most on width, payload, height ceiling, and vertical step granularity [S1][S2][S7]. On tray width, White Systems offers 96, 120, and 144 inches as common values, Modula Lift covers 1,500 to 4,100 mm (about 59 to 161 inches), and Southwest Solutions publishes a 4 to 12 foot window in 6-inch increments, so the comparison is finer on the Southwest line and broader on the Modula metric line [S2][S3][S6]. On per-tray payload, White Systems reaches 3,300 lb per tray, Modula Lift and Pallet cap at 2,200 lb, and Modula Next caps at 1,102 lb, placing the White Systems heavy line at the top of the surveyed envelope [S1][S2]. On unit height, LOGIMAT goes furthest at up to 78 feet in 4-inch increments, Modula's Flexibox and lift lines reach 68 ft 11 in, and the Modula slim module is restricted to under 23 feet for constrained sites [S1][S7]. On vertical step granularity, LOGIMAT's 4-inch step is the tightest, White Systems uses 5.9 inch steps, and Modula's range is published as fixed model-level breakpoints, so LOGIMAT has the most ceiling-fit headroom and Modula's slim module has the least [S1][S2][S7].
When Standard Tray Sizes Fit, and When They Do Not
Standard VLM tray sizes fit operations with a single dominant SKU profile, a known clear ceiling, and no need for unusual part aspect ratios, which describes most general parts, MRO, and ecommerce backstock deployments [S4][S5]. They do not fit operations with very long bar stock, sheet metal, or odd-form parts, where a vertical lift module tray cannot present the part ergonomically and a dedicated bar stock VLS or sheet metal VLS is the correct product family [S4]. They also do not fit facilities where the floor-to-ceiling clear height sits outside the OEM's published range, because no standard tray will compensate for a unit that physically cannot be installed, which is why most OEMs build to within 4 to 6 inches of the ceiling using their published vertical increments [S1][S2][S7]. Custom tray sizes are widely available across the major OEMs, with Vidir Solutions explicitly publishing VLM customization for ceiling height, load capacity, and tray size as a standard offering rather than an exception [S4].
For facilities comparing the storage class against broader high-density options, the vertical lift module sits in a different envelope than cable tray systems or linear module automation, and the tray-dimension question only matters once the operations team has decided a VLM is the right storage class. The two trackable signals to watch through the rest of 2026 are LOGIMAT-style 4-inch vertical increments being adopted by other OEMs to tighten ceiling fit, and SSI-style multi-unit linking being extended past the current 78 foot single-unit cap into linked stacks above 100 feet.