Server Rack Rails Buying Guide: Everything You Need To Know


Choosing the right server rails is essential for proper installation and accessibility. However, selecting rack rails can be confusing if you’re not sure where to start. To ensure that you select the correct rail kit, this comprehensive guide will help you understand what a server rail is, how to differentiate the types of rails, and key factors to consider for your business. 

What is a Server Rack Rail? 

Server rack rails are essentially metal brackets or frames used to the mount and secure server within a 19” server rack or cabinet. They ensure that you can organize, access, and secure your servers. Because server rails provide stability and support, it allows for efficient installation, maintenance, and management of your systems. 

Without rack rails, your servers would become prone to consequences such as equipment damage, overheating issues, and disorganization. Overall, rack rails are a crucial component to have because they can optimize server performance, improve airflow, and simplify server management. 

The Different Types of Server Rails

Additionally, rack rails are specifically designed for the rack or equipment that you are using, so you can choose a rail kit that will best suit your needs. Two rails are typically required to mount your equipment, so every rail kit will come in pairs. These rails are made from steel or aluminum, featuring robust construction. Before you select a rail kit, it’s important to understand the difference between the different types and their uses. 

Sliding Rails / Telescoping

Sliding rails, or telescoping rails allow you to easily access your servers. As the name implies, sliding rails feature a sliding mechanism that allows you to fully extend a server out of the rack, similar to opening a desk drawer. With slide rails, you can service your equipment without disconnecting all the cables. For those environments with limited space or those who need to immediately service their equipment, sliding rails are ideal in comparison to fixed rails. 

Sliding Rack Rail
Sliding Rack Rail

Fixed Rails / Static Rails    

Fixed rails, or static rails, are typically for servers that do not require frequent maintenance or access. They are a long L-shaped bracket that supports the edge of your equipment. However, these rails firmly fix the server to the rack in a set position, so they are not flexible when it comes to server positioning. To perform maintenance, you need to fully remove the server and equipment from the server rack.  

Fixed rail kits do provide a cost-effective solution since they are generally less expensive. For large data centers or businesses that require a large amount of rack rails, fixed rails provide a significant amount of savings and secure mounting solution compared to sliding rail kits.

Fixed Rack Rail
Fixed Rack Rail

Universal Rails

If you want to avoid the ongoing expense of repurchasing rails kits, then universal rails are the solution. Our universal rails are designed as an alternative for the standard issued OEM rails by HP, IBM, Dell, and other leading OEM server manufacturers. These rack mount rails are a fixed rail type, providing a flexible solution for incompatible rack rails within 19” server racks. 

Furthermore, the universal rails are not limited to 19” racks. Depending on your needs, you can attach them to server racks that are wider or narrower. We offer 1U, 2U, or 3U universal rails that can support a variety of server racks, including those with square, round, and threaded holes. 

universal rails 1U
Universal Rack Rails

What is Rack Mounting Depth? 

When installing rack rails, you need to understand the mounting depth of your rack. Rack mount depth is commonly confused with the overall rack depth including the door. However, the mounting depth is actually the dimension from the front mounting post to the back mounting post. It refers to the area in which your rack allows you to install rails or shelves. 

Most server racks have adjustable mounting posts, so you can only determine the accurate depth by measuring it. This ensures that your server rails will fit inside the rack. 

Rack Mounting Depth
Rack Mounting Depth

The OEM standard depths include: Dell (28 7/8″), HP (29 1/8″), and IBM (28 1/2″). As a result, the common depth is now approximately 29″ since this is close to all OEM standards. Any depth greater than 29” provides extra support for cable management and additional accessories. 

How To Select The Right Server Rails

Selecting the right server rack rails for your business is essential for ensuring proper installation and accessibility. Key factors to consider when making your decision include: server size and configuration, accessibility, weight capacity, available rack space, cable management, and installation ease. 

Server Size and Configuration

First, you need to determine the size and configuration of your server to ensure that the rails you select will properly accommodate them. This means knowing the mountable width, depth and height of your server. Once you know those measurements, you need to make sure that your server is compatible with the mounting height, width, and depth size of your server rack. To read more about server rack sizes, check out our Server Rack Buying Guide


Second, it is important to consider how often you will access your servers for maintenance or upgrades. If you plan to frequently access your servers, then sliding rails are a convenient choice since it allows for easy removal. 

Weight Capacity 

Third, you need to check the weight capacity of the server rails. This will ensure that they can support the weight of your servers. If you have larger servers or equipment, then rails that will support heavier servers are beneficial. 

Rack Space 

Fourth, you need to evaluate the available rack space in your server room. If the rack space is limited, then you should select sliding rails that allow for compact server positioning. 

Cable Management 

Fifth, a cable management arm can improve your experience when using sliding rails. While cable management is commonly discussed in the IT industry, cable management arms are easily forgotten, even though they are essential for quick deployment. For a clutter free workspace, a cable management arm will organize data and power cables to optimize the available area. To read more about the benefits of using a cable management arm, check out our blog here.

Cable Management Arm
Cable Management Arm

Installation Ease 

Lastly, installing and setting up server rails is a crucial step in ensuring proper server management. While some server rails require additional tools for installation, other rails are tool-less. You need to consider your server rail preference and the level of convenience you require for the installation process. 

How To Rack a Server

When installing a server, there are 4 key steps to lowering risk of damaging components and ensuring stability.

1. Mount the server in the rack – Once your depth is adjusted, you will be able to mount your rails. Depending on the rack hole type and mounting mechanism of the equipment, instructions will vary. For your reference, here are instructions on mounting threaded, universal rails, and square hole with cage nut variants.

mount tool-less rail on rack

2. Install the inner rail into the server via shoulder screws (for server specific rails) – Rack rails that are specifically designed to work with servers such as Dell or HP will have shoulder screws. These shoulder screws stick out of the sides of servers and look similar to small knobs. They attach to the j slot of the server rail to lock it in place and make it so that metal is not on the top or bottom of the server.

install inner rail to server

3. Slide the server into the rack – If you are using a server specific rail, you need to match the inner rails on your server up with the outer rails mounted on the rack and slide it in. For universal rails, you would not have installed anything to your server chassis and will be able to slide it onto the rail.

sliding shelf onto rack

4. Install the thumb screw if using a compatible server – Universal rails come with support for thumb screws. This locks the server into the middle hole of a rack unit. Not all server chassis support thumb screws, but it’s a good idea to install the thumb screws if your server supports it. 

Server Rail Kit Compatibility 

RackSolutions offers a large selection of server rack rails as an alternative or replacement to OEM rail kits. We have multiple sliding or fixed rack rail kits available for Dell, HP, and IBM/Lenovo. Many of our sliding rail kits also include an integrated cable management arm. Before selecting a server rail, you need to identify your server model.

Identifying Dell Server Model

Dell PowerEdge servers with common design components are grouped into generations. The server naming of models can provide insight to the generation, class of system, form factor or CPU socket count. To learn more about the Dell PowerEdge Server Naming Convention, check out our Dell Product Guide. You can also refer to Dell Support for more information on identifying your server’s model number. 

Identifying HP Server Model

If you have an HP server model, the product number is located on the server itself or on the warranty card. HPE PartSurfer is another way to find fast and easy access to service parts information as well. By using PartSurfer, you will be able to: 

  1. Search for part information by product number, serial number, model name, or part number
  2. Identify all HPE products that use/reference a specific part number
  3. Filter your search results by part keyword or category
  4. Display product exploded view diagrams and part photographs
  5. Generate on-screen and printable reports

If you don’t know the product number, then you can enter the product’s service tag. To learn more about identifying your HP Server Model, check out our HP Product Guide

HP Product's Service Tag
HP Product’s Service Tag

IBM / Lenovo Server Model

For those with IBM and Lenovo servers, you can identify the IBM server serial number by referring to the machine identification and serial number labels on the back or bottom of the machine. You can also refer to IBM Support for more information on identifying your server’s model number. 

IBM Server Model Number
IBM Server Model Number

RackSolutions Specs and Rack Compatibility  

To learn more about the specific server specifications for your server, our rail guides provide information on compatible mounting equipment. Each rail guide includes direct links to mounting products that are compatible with your servers and information about dimensional limitations. Mounting products include slide rails, universal rails, standard EIA 19 inch racks, rack shelves, cable management, adapters, and a universal rack-to-tower conversion kit. 

Rail Compatibility Guides
Rail Compatibility Guides

Do You Need a Custom Rail Kit? 

RackSolutions is ready to create custom products for your specific needs. We can design solutions and immediately send out prototypes. We design our long-lasting rail kits in house. If you need a custom rack rail kit, then we can make it happen. Contact us today and we’ll be ready to discuss with you! 


FAQs: Server Rack Rails

What U height should my rail be?
If you are buying rails which are designed for a specific server, they are already sized to be the optimal U height for that piece of equipment. Universal rails, on the other hand, will be able to hold your server as long as it is under the weight capacity. For instance a 1U universal rail can hold a 2U server as long as that server is less than 45 lbs. Best practice is to purchase a rail that takes up the same number of rack units as your server.

What’s the difference between mounting depth and equipment depth? 

Mounting depth refers to what sized rack the rail will fit inside. For example, a Cobra 90 Rail (opens in a new tab) with a mounting depth range of 20” – 30” will fit inside of racks with 20” – 30” of space between the connection points on the uprights.

Equipment depth, on the other hand, describes what length equipment must be to fit on the rail. A universal rail can mount equipment up to 35” deep. This is mostly relevant to rails that are compatible with multiple servers.

What’s the easiest way to install cage nuts? 

Before installing your server rails, we recommend picking up our Cage Nut Tool. You can install cage nuts without tools, but after putting in more than a few, it can be uncomfortable and potentially hurt your hand.

World's Best Cage Nut Tool 
World’s Best Cage Nut Tool

Is hardware included with the rack rails ?

Most of our rails work with square, round and threaded hole racks. All hardware to mount the rails in any type of rack is included. All you’ll need is a phillips head screwdriver, unless you’re using our tool-less rails in which case you don’t need any tools at all.

Server Rack Rails Buying Guide: Everything You Need To Know
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Server Rack Rails Buying Guide: Everything You Need To Know
Server rack rails are essentially metal brackets or frames used to the mount and secure server within a 19” server rack or cabinet. They ensure that you can organize, access, and secure your servers. Because server rails provide stability and support, it allows for efficient installation, maintenance, and management of your systems. 
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