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It explains what “tandem” means in crane lifting, outlines lift configurations using 40’ and 20’ containers, and compares single-hoist versus dual-hoist tandem cranes. The talk highlights benefits and drawbacks, including conversion capability, unequal-height stack handling, maintenance requirements, additional weight, and cost premium. It also covers primary hoist selection, ordered capacity patterns, and how increased wheel loads can be managed by increasing rail gage to improve stability and clearance.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":40,"@type":76,"position":81},"https://docshare.wps.com/document/research-report/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/tandem-40-dockside-cranes-and-their-impact-on-terminals-presentation/649392/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/tandem-40-dockside-cranes-and-their-impact-on-terminals-presentation/649392.png","ImageObject",300,407,{"name":92,"@type":93},"Liam","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-11-03","2026-10-23",true,{"@type":102,"interactionType":103,"userInteractionCount":19},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What does “tandem” mean for dockside crane lifts?","Question",{"text":112,"@type":113},"Tandem lifts lift multiple adjacent containers together as they move along the trolley travel direction. The talk notes that different tandem lift configurations can use either 40’ or 20’ containers.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"What are the main differences between single-hoist and dual-hoist tandem cranes?",{"text":117,"@type":113},"Single-hoist tandem cranes use one hoist system and mainly differ in hoist capacity and control considerations, with limited access to unequal-height stacks. Dual-hoist tandem cranes use two separate hoist systems, making conversion easier for unequal-height stacks but requiring additional maintenance and extra weight.",{"name":119,"@type":110,"acceptedAnswer":120},"How does tandem crane operation affect wheel loads and terminal infrastructure?",{"text":121,"@type":113},"Due to increased weight and lifted loads, tandem cranes produce higher wheel loads, about 35–40% higher than single-lift cranes for the same configuration. The presentation suggests increasing rail gage to reduce wheel loads, improve stability, and provide more space under the crane for increased truck traffic.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},649392,1792799648,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":39,"category_name":40,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":19,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":139,"language":140,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":67,"update_tm":129,"read_time":144},8796095461564,"https://ap-avatar.wpscdn.com/davatar_155a257f0dc6eb9ab79c44ca47cae57d","ASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nGood afternoon. I’m Derrick Lind with Liftech Consultants.  \nI’ll be talking about “Tandem 40 Dockside Cranes and Their Impact on Terminals”. Tandem cranes are no longer a fantasy. These cranes are being used at many terminals throughout the world.  \nASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nSo, what is meant by “tandem”. Everyone is probably familiar with the term “twintwenty”, but “tandem” is relatively new.  \nAs shown, tandem lifts are when multiple containers which are adjacent to eachother in the trolley travel direction are lifted.  \nDifferent types of tandem lifts are possible with either 40’ or 20’ containers.  \nASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nGenerally, there are two types of tandem cranes; single-hoist or dual-hoist.  \nI’ll focus mostly on dual-hoist cranes. However, both types share many of the same considerations.  \nASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nSingle hoist tandem cranes use one hoist system to lift the tandem load.  \nThe hoist system is conventional, except for the hoist capacity, lift system, and control systems. Also, the additional load applied to the crane must be considered in the design.  \nSome benefits of a single hoist tandem crane are: One hoist system = less cost/maintenance  \nPossible to convert an existing crane to tandem operations  \nSome problems with a single hoist tandem crane are: Limited access to unequal height stacks Reduced hoist capacity  \nSlow conversion to single lifts, because the special tandem lift system must be removed.  \nASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nDual-hoist tandem cranes use two separate hoist systems to lift the tandem load.  \nCurrently, about 50 ZPMC DHT40 have been delivered, mostly to Chinese ports. 80 more are on order.  \nSome benefits of dual-hoist tandem cranes are: Easily converts to single lift operation Handles unequal height stacks  \nSome problems with dual-hoist tandem cranes are : Additional maintenance due to two hoist systems Additional weight  \nAdditional initial cost-approximately 20% -30% premium over single-lift cranes  \nASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nFor most dual-hoist tandem cranes, the landside hoist is considered the primary hoist system. Typically it has a higher lift capacity.  \nApproximately 90% of DHT40’s ordered have an 80 LT total capacity. Only a few have been 120 LT.  \nASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nDue to the increased weight and lifted loads, tandem cranes have higher wheel loads.  \nFor the same configuration, wheel loads for tandem cranes are approximately 35- 40% higher than single-lift cranes.  \nOne way to address the increased wheel loads is to increase the rail gage.  \nASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nIn addition to reducing wheel loads, increasing the gage improves stability and provides more space under the crane. The additional lanes will help with increased truck traffic.  \nASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nThe major differences between DHT40 and single lift cranes are: Two Main Hoist Systems  \nDHT40 Trolley  \nComplex Dual Head Blocks  \nSpecial Operator Controls  \nASCE Ports 2007 Conference, San Diego, CA Derrick Lind, Liftech Consultants Inc.  \nMarch 27, 2007  \nDHT40 trolleys are relatively conventional. They are longer to accommodate two sets of hoist sheaves. They also have headblock stowage brackets underneath.  \nNote the additional hoist set of ropes.","cbCaipvB67DJkiu0","https://ap.wps.com/l/cbCaipvB67DJkiu0","pdf",3799419,33,"English","# Tandem crane overview\n## Meaning of “tandem” lifts\n## Types: single-hoist vs dual-hoist\n# Single-hoist tandem cranes\n## Benefits\n## Problems\n# Dual-hoist tandem cranes\n## Benefits\n## Problems\n# Key design and capacity considerations\n## Primary hoist system\n## Wheel loads and rail gage improvements\n# Major differences vs single-lift cranes\n## DHT40 trolley and controls","[{\"question\":\"What does “tandem” mean for dockside crane lifts?\",\"answer\":\"Tandem lifts lift multiple adjacent containers together as they move along the trolley travel direction. The talk notes that different tandem lift configurations can use either 40’ or 20’ containers.\"},{\"question\":\"What are the main differences between single-hoist and dual-hoist tandem cranes?\",\"answer\":\"Single-hoist tandem cranes use one hoist system and mainly differ in hoist capacity and control considerations, with limited access to unequal-height stacks. Dual-hoist tandem cranes use two separate hoist systems, making conversion easier for unequal-height stacks but requiring additional maintenance and extra weight.\"},{\"question\":\"How does tandem crane operation affect wheel loads and terminal infrastructure?\",\"answer\":\"Due to increased weight and lifted loads, tandem cranes produce higher wheel loads, about 35–40% higher than single-lift cranes for the same configuration. The presentation suggests increasing rail gage to reduce wheel loads, improve stability, and provide more space under the crane for increased truck traffic.\"}]","Tandem 40 Dockside Cranes and Their Impact on Terminals - Presentation | PDF",83]