Back Amongst Friends, Blocked Road, and Clear the Way are quests in Chapter 11, "Haunted", in Final Fantasy VII Remake, taking place in the Train Graveyard. After traveling through a maintenance facility in the graveyard, Cloud Strife, Aerith Gainsborough, and Tifa Lockhart look for a way back to the Sector 7 Slums.
After leaving the maintenance facility, interact with the lever on the left to move a train turntable. As it moves, wererats, ghosts, and cripshays are fought; wererats and cripshays can be killed with simple attacks, while ghosts should be defeated with magic spells preferably from the Fire Materia, or just with abilities while they are not immune to physical damage. Use Aerith to focus on the ghosts, while Tifa and Cloud focus on cripshays and wererats before turning their attention to the ghosts themselves.
Once the enemies are defeated, cross the newly-created bridge and take the ladder up to the top of an abandoned carriage, move forward, and then take the ladder down to the ground. Use a ladder inside a nearby train and activate it. After the cutscene, leave the train and use a ladder up to the side of a train in the northeast, then cross it and follow a path across several trains, then use the ladder to drop down to the ground before heading north through an abandoned carriage to the northeast portion of the map. Enter the abandoned train on the right and activate it, and head right around the train after it moves to pick up a treasure chest with two mega-potions, then back left to a wider area.
Here, a lesser drake and a cerulean drake are fought. Though the cerulean drake is tougher, the strategy is the same; use ranged attacks as Aerith and aerial attacks as Cloud and Tifa until they lower or are pressured, then unleash character attacks against them. To the right of here, a final train can be activated to create a complete path across. To cross the path, head southeast and use the ladder onto a train, and follow the connected trains across to the other side. A ladder drops down to the other side, where a bench and vending machine are located.
Use the bench to restore HP/MP, and prepare for a boss battle. The upcoming boss is weak against Ice, meaning the Ice Materia is useful against it. Despite this, Lightning Materia may be ideal for the guaranteed hit instead. The player can also equip the steal materia to steal the Bladed Staff. Wind Materia is also useful against it, as hitting it with wind attacks while it is airborne is a useful tactic. Equipping Cleansing Materia to cast Esuna, as well as equipping Warding Materia paired with Binding Materia, can help deal with its attacks that inflict Sleep.
Shiva Materia should be equipped. Once prepared, head left to begin the battle.
Eligor is capable of using strong melee attacks which should be avoided, and can make itself immune to physical damage. At this stage, cast spells against it to deal damage and increase its stagger gauge. Once staggered, lay into it with powerful attacks, and use Tifa's Unbridled Strength martial techniques and Aerith's Ray of Judgement to increase its stagger gauge, while laying into it with Cloud's abilities.
After losing a third of its HP, Eligor is capable of going airborne, and will use Reflect on itself. Wait for reflect to end, and then cast Aerora or Aero to bring it to the ground. Eligor's Piercing Glaze should be avoided, as this can sleep a character. Its Javelin Bolts attack can be avoided, though characters not in range can take advantage of this to cast spells while it is stationary. Beyond this, the strategy remains the same as before.
After losing another third of its HP, it will sometimes ride around the area, making it invulnerable to damage. Its right wheel and left wheel can be crippled (which is easily done using a limit break); crippling one will cause it to be stationary, and crippling the other can easily stagger it.
Once Eligor is defeated, a cutscene commences. After this, head straight forward to a fence, at which point a cutscene commences, leading into the next quest, "Head for the Pillar" in the following chapter, "Fight for Survival".
Hard mode tips
For the battle around the turntable, it is better to preserve MP however possible. Prayer Materia is preferable for healing. Aerith should use Soul Drain often, and she can still cast spells if paired with MP Absorption Materia, against ghosts that become immune to physical damage. Cloud and Tifa can focus entirely on physical damage here, with Cloud using Triple Slash to clear waves while Tifa focuses on individual targets. Against the drakes, the same applies, though Aerith can use lightning materia to cast spells guaranteed to hit.
Against Eligor, prayer materia is vital, as during its second phase it will be able to inflict a permanent Reflect status on the entire party, making healing spells irrelevant. Chakra Materia is also useful for much the same reason, and Steadfast Block Materia is vital especially on Cloud. ATB Stagger Materia is very important for Tifa. Time Materia is important especially for the final phase, as though the boss can resist it after a few uses, it is not immune to Stop. Cleansing Materia can be equipped and paired with Magnify Materia to cast Resist, though it can just as easily be paired with time materia to cast Haste on all.
Either ice or lightning materia should be equipped on all characters, where ice can be paired with elemental materia and its spells cast while it is staggered or grounded, and lightning provides guaranteed hits. Aerith's Arcane Ward will be very useful, and all party members can equip weapons giving them mixed attributes to allow them to play a spellcasting role. Cloud and Tifa's physical attacks should be used.
Early on, the best method is to use Cloud's Counterstance against Eligor's early attacks, as the easiest way to maximize damage output, while Aerith casts Blizzard whenever it is stationary. Most other characters should remain defensive until Eligor is pressured after an attack. It is possible to stagger him, and thus Tifa's Unbridled Strength should remain at maximum to boost its stagger gauge, as Aerith casts Blizzaga.
In the second phase, when Eligor raises in the sky and hits everyone with Reflect, Aerith should use Arcane Ward, and the party should remain defensive until Eligor's own Reflect ends. At this point, the party should cast Thundaga from within the ward, causing guaranteed hits. Between this, Tifa can use aerial attacks while it is using Javelin Bolts. When it is on the ground, Blizzard can be cast to pressure and stagger it.
For the final phase, as in normal difficulty, destroy the wheels and focus on staggering it. Cast Stop on it to allow time to destroy the wheels, and focus on building its stagger gauge. While it does move around the arena, use Cloud's Counterstance to intercept it again. After destroying both of its legs, it will be staggered; use Tifa's True Strike and her Unbridled Strength techniques to build its stagger bonus damage, while Aerith casts spells and Cloud uses Infinity's End.
Defeating Eligor will reward Tifa the Way of the Fist Vol. VIII.