LTW's patented order picking gate: The innovative third provisioning strategy in order picking

Why the intralogistics industry has overlooked such a simple yet ingenious concept for far too long

In an industry increasingly dominated by megatrends such as autonomous mobile robots, AI-controlled driving strategies, and shuttle systems, a horizontally sliding gate might seem unremarkable at first glance. Yet, this very unassuming simplicity is the secret to the success of the patented picking gate system from LTW Intralogistics GmbH in Wolfurt, Vorarlberg. The system solves a problem that has plagued intralogistics for decades: the safe execution of order picking operations directly at the aisle of a storage and retrieval machine without significantly disrupting automated operation. What appears at first glance to be a minor mechanical detail reveals itself upon closer inspection as a sophisticated solution to a whole host of economic, safety, and operational challenges.

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The gap between man and machine in the high-bay warehouse

Order picking has always been considered one of the most complex and costly processes within the entire intralogistics chain. Essentially, it involves assembling goods from a warehouse system to fulfill a specific order. The industry generally distinguishes between two strategies: goods-to-person picking, where the goods are automatically transported to the picker, and the person-to-goods principle, where the employee goes to the storage location.

With the goods-to-person approach, staff walking distances are almost entirely eliminated, significantly increasing picking performance and reducing error rates. However, this strategy requires substantial investment in automated racking and retrieval systems and offers little flexibility in the face of fluctuating demand. A conveyor system failure can lead to a complete warehouse shutdown. The person-to-goods strategy, on the other hand, is more flexible and less expensive to invest in, but results in longer travel times, higher staffing costs, and a greater susceptibility to errors.

The LTW picking gate system fills precisely this gap. It enables direct order picking at the aisle of the high-bay warehouse, thus combining the advantages of both strategies: The goods are automatically retrieved by the storage and retrieval machine to the defined picking station, while the employee gains safe access to the goods via so-called picking tunnels. The horizontally sliding gates physically separate the storage and retrieval machine aisle from the picking area and only open when goods are transferred from the racking area to the picking area.

A surprisingly simple design principle with enormous impact

The system's technical elegance lies in its structural simplicity. The picking doors are integrated into the racking system and can be moved horizontally to separate automated and manual handling areas. Only one drive unit is required per picking level and side on the storage and retrieval machine. This single drive unit replaces the otherwise necessary multitude of additional drives and their complex wiring.

The economic implications of this design principle are remarkable. In a typical high-bay warehouse with multiple picking levels, conventional access control would require a separate drive and individual wiring for each access point. The LTW system dramatically reduces this complexity. Furthermore, the low weight of the doors has a significant impact on the racking structure. In high-bay warehouses, which in Germany are permitted to reach heights of up to 50 meters, every additional kilogram on the racking structure represents a structural cost factor, resulting in larger support profiles, reinforced foundations, and increased material costs. A lightweight door system relieves the entire supporting structure and can thus positively influence the investment costs of the racking building itself.

Furthermore, according to the manufacturer, the gates require very little maintenance. The mechanical design is deliberately kept simple, while the drive concept is highly sophisticated. This principle of combining mechanical simplicity with intelligent drive technology reflects an engineering philosophy that often makes the difference in intralogistics between theoretically brilliant and practically robust solutions.

The underestimated danger: Security as an economic imperative

The safety dimension of the picking door system becomes clear against the backdrop of alarming accident statistics in warehouse logistics. The German Social Accident Insurance (DGUV) reports that in 2019, approximately 228,000 accidents occurred on transport routes within the company or its surrounding environment, 89,000 of which took place during storage processes. The DGUV accident statistics for 2021 alone documented 83,098 workplace accidents related to conveying, transport, and storage equipment, including 34,051 involving material handling trolleys and forklifts. Around 16,429 accidents involved racking systems, pallets, and shelves. In the same year, 15,383 forklift accidents were reported, representing an increase of 12.4 percent compared to the previous year, eleven of which were fatal.

The LTW picking gate system specifically addresses the need to protect the picking area from falls, crushing, and shearing hazards in relation to the aisle of the stacker crane. These three hazard categories are among the most serious risks in high-bay warehouses. In narrow-aisle systems, the uncontrolled presence of personnel in the aisles is generally prohibited due to the high risk of accidents caused by moving stacker cranes. However, if picking operations must be carried out directly at the aisle, an inherent conflict arises between productivity and safety. The physical separation provided by the picking gates elegantly resolves this conflict: The picker has access to the goods without ever being exposed to the aisle and thus the operating space of the stacker crane.

This safety innovation is also economically relevant. In 2016, over 800,000 workplace accidents resulting in at least three days of sick leave were reported in Germany, with almost ten percent occurring during warehouse work. According to industry estimates, the costs of a workplace accident resulting in illness exceed preventive investments in safety technology tenfold. In cases of serious accidents where the employer is partly at fault, costly and even criminal consequences are possible. From this perspective, investing in an integrated safety system like the order picking gate is not merely a cost factor, but a risk-reducing measure with a demonstrable return on investment.

LTW: From a one-man operation to an international full-service provider

The company behind the picking gate is itself a remarkable economic success story. LTW Intralogistics was founded in 1981 as a division of the Doppelmayr Group, the world market leader in ropeway construction, headquartered in Wolfurt, Vorarlberg. The initial impetus for its founding was pragmatic: Doppelmayr wanted to compensate for seasonal fluctuations in manufacturing and production capacity utilization inherent in the project-based ropeway business. What began as a one-man operation in the logistics sector developed, under the leadership of Peter Malin and with its own patents, into an internationally operating full-service provider.

Today, LTW employs around 320 people at four locations, including its headquarters in Wolfurt, a branch in Illerkirchberg near Ulm, an office in Vienna, and a location in Denver, USA. The company generated sales of €66.2 million in 2019. Its parent company, the Doppelmayr Group, recorded total sales of €1,057 million in the 2023/24 financial year with 3,517 employees worldwide.

LTW's affiliation with the Doppelmayr Group is strategically significant. The manufacturing of its stacker cranes and conveyor technology components adheres to cable car standards at the parent company. This quality standard, stemming from the extreme demands of cable car construction regarding technology, safety, and material durability, is consistently applied to intralogistics products. LTW positions itself as a full-service provider, supplying stacker cranes, conveyor technology, and its proprietary LIOS warehouse management software from a single source, thus enabling seamless material flows in high-bay warehouses.

LTW Intralogistics Solutions – Picking Door – Image: LTW Intralogistics GmbH

LTW offers its customers not individual components, but integrated complete solutions. Consulting, planning, mechanical and electrotechnical components, control and automation technology, as well as software and service – everything is networked and precisely coordinated.

In-house production of key components is particularly advantageous. This allows for optimal control of quality, supply chains, and interfaces.

LTW stands for reliability, transparency, and collaborative partnership. Loyalty and honesty are firmly anchored in the company's philosophy – a handshake still means something here.

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• LTW Solutions

The market context: Why intralogistics automation is booming

LTW's picking door system demonstrates its economic relevance against the backdrop of a rapidly growing market. The global market for intralogistics automation solutions was valued at US$48.21 billion in 2024 and is projected to reach US$86.72 billion by 2035, representing an average annual growth rate of 5.48 percent. In Europe, the market is experiencing even more dynamic growth, with a projected growth rate of 11.60 percent between 2024 and 2029. The specific market for storage and retrieval machines is expected to grow from US$1.1 billion to US$2.0 billion by 2034, with an annual growth rate of approximately 6.2 percent.

This growth is driven by several megatrends. The e-commerce boom demands maximum speed, the highest precision, and perfect space utilization in warehousing. Exploding costs for warehouse space make vertical space utilization in high-bay warehouses economically essential. And the acute shortage of skilled workers in logistics is further accelerating automation: In the fourth quarter of 2024, around 45 percent of warehousing companies reported that their business operations were hampered by a lack of skilled workers. According to IAB statistics, over 60,000 positions in warehouse logistics were vacant in 2025. The organizational consultancy Korn Ferry forecasts a global skills shortage of 85.3 percent for the logistics supply chains by 2030.

In this environment, hybrid solutions that combine human flexibility with machine efficiency are gaining importance. Hybrid systems will be a key theme by 2026: Mobile robots will be combined with stationary automation systems such as stacker cranes, with each system deployed where it can best leverage its strengths. The LTW picking gate integrates seamlessly into this hybrid approach, as it provides precisely the controlled interface between automated warehouse operations and manual order picking.

Economic calculation: When does the system pay off?

The economic attractiveness of the picking door system can be assessed along several dimensions. First, there are the direct cost savings resulting from the reduced drive requirements: Instead of installing a separate drive and cabling for each individual picking station, one drive per picking level and side on the storage and retrieval machine is sufficient. In a typical high-bay warehouse with, for example, eight picking levels and access from both sides of the aisle, the drive requirement is reduced from potentially over a dozen to just the system's own drives on the storage and retrieval machine. The savings in costs for motors, control electronics, cable harnesses, installation labor, and subsequent maintenance add up to considerable sums over the service life of a high-bay warehouse, which is typically 20 to 30 years.

Secondly, there are the structural savings: The low weight of the gates reduces the load on the racking structure. In a high-bay warehouse, which is defined as such from a height of 12 meters and can reach up to 50 meters in Germany, the weight savings increase exponentially with each additional level. The resulting relief of the supporting structure allows for slimmer rack profiles and lighter foundations, which is reflected in the steel construction and building costs.

Thirdly, the safety return: Preventing workplace accidents through the physical separation of people and storage and retrieval machines not only reduces direct accident costs such as downtime, medical treatment, and insurance premiums, but also eliminates the risk of production interruptions and regulatory sanctions. Given that the costs of a workplace accident far exceed the investment in prevention, this results in a particularly favorable cost-benefit ratio.

The software component: LIOS as a strategic lever

An often overlooked aspect of the picking gate system is its integration with LTW's proprietary intralogistics software, LIOS. This warehouse management system defines the strategy for where goods are retrieved and picked. The gates don't open arbitrarily, but rather are controlled by the software logic, which determines the optimal picking location by considering route optimization, order prioritization, and capacity balancing. LIOS supports a wide range of picking solutions and also provides suitable mobile devices for warehouse staff, including pick-by-light, pick-by-voice, and tablet-based systems.

This software integration is key to the system's scalability. Companies are increasingly using software solutions to handle and pick more goods in the warehouse with their existing workforce. Real-time data exchange between transporters and the warehouse enables precise preparation for goods movements and reduces waiting times. Industry experts predict that by 2026, AI at the interface between storage and retrieval machines and autonomous mobile robots will support dynamic task distribution, taking into account real-time bottlenecks, battery status, and downstream capacity. In such an environment, software-controlled operation of picking doors is a natural component of an increasingly intelligent warehouse system.

Critical assessment: Limits and challenges

While acknowledging its technical elegance and economic logic, the system must also be critically evaluated. Order picking directly at the aisle, based on the person-to-goods principle, requires that the product structure and material flow justify such an approach. For companies with extremely high throughput and standardized load carriers, a fully automated goods-to-person solution may be the superior option despite the higher investment. The picking gate tends to be better suited for applications where a diverse product range, varying container sizes, or the need for visual quality control necessitates human intervention in the picking process.

Furthermore, person-to-goods order picking remains more labor-intensive than fully automated solutions. At a time when around 45 percent of warehousing companies complain about a shortage of skilled workers and over 60,000 positions in warehouse logistics are vacant, this very personnel requirement can become a limiting factor. The future, therefore, likely lies in hybrid configurations that combine the picking door system with robot-assisted order picking, for example, through the use of cobots or picking robots that access the provided goods from the safe side of the door.

Another challenge lies in retrofitting. While the system can be integrated into the racking structure of new high-bay warehouses from the outset, retrofitting existing systems is more complex due to the necessary structural modifications to the racking system and the control software of the storage and retrieval machine. For the growing retrofit market, which is gaining importance given the large number of aging high-bay warehouses, a modular retrofit solution would be a valuable addition to the product range.

An inconspicuous building block with strategic depth

LTW's picking door system isn't the kind of product that makes headlines at trade fairs. There's no AI algorithm grabbing attention, no autonomously navigating robot captivating the audience. Instead, it's a sophisticated engineering solution that addresses a critical interface in intralogistics, where automated warehouse operations and human order picking intersect. The reduction to a single drive per picking level, the lightweight doors, the low-maintenance mechanics, and the software-controlled operation combine to create a system that offers significant added value in terms of economy, safety, and operational efficiency.

In an industry characterized by a global market volume exceeding US$48 billion for automation solutions, and where the European market is expanding at double-digit growth rates, LTW's unique achievement lies in not following the trend of maximum automation at any cost, but rather in having developed a pragmatic solution for real-world operations. LTW, a company with roots in cable car construction and manufacturing its products to cable car standards, brings an engineering culture to intralogistics where safety, robustness, and durability are not afterthoughts, but inherent in the product from the ground up. The patented picking gate is a prime example of how true innovation in industrial logistics doesn't always have to look spectacular, as long as it solves the right problems in the right way.

Konrad Wolfenstein

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