diff --git a/osu.Game.Rulesets.Mania/Mods/IGenerateSpeedAdjustments.cs b/osu.Game.Rulesets.Mania/Mods/IGenerateSpeedAdjustments.cs
index 1545f4cf89..f179aa2ff8 100644
--- a/osu.Game.Rulesets.Mania/Mods/IGenerateSpeedAdjustments.cs
+++ b/osu.Game.Rulesets.Mania/Mods/IGenerateSpeedAdjustments.cs
@@ -7,8 +7,17 @@ using osu.Game.Rulesets.Timing;
 
 namespace osu.Game.Rulesets.Mania.Mods
 {
+    /// <summary>
+    /// A type of mod which generates speed adjustments that scroll the hit objects and bar lines.
+    /// </summary>
     internal interface IGenerateSpeedAdjustments
     {
+        /// <summary>
+        /// Applies this mod to a hit renderer.
+        /// </summary>
+        /// <param name="hitRenderer">The hit renderer to apply to.</param>
+        /// <param name="hitObjectTimingChanges">The per-column list of speed adjustments for hit objects.</param>
+        /// <param name="barlineTimingChanges">The list of speed adjustments for bar lines.</param>
         void ApplyToHitRenderer(ManiaHitRenderer hitRenderer, ref List<SpeedAdjustmentContainer>[] hitObjectTimingChanges, ref List<SpeedAdjustmentContainer> barlineTimingChanges);
     }
 }
diff --git a/osu.Game.Rulesets.Mania/Mods/ManiaModGravity.cs b/osu.Game.Rulesets.Mania/Mods/ManiaModGravity.cs
index d36b187599..1ba8ac4710 100644
--- a/osu.Game.Rulesets.Mania/Mods/ManiaModGravity.cs
+++ b/osu.Game.Rulesets.Mania/Mods/ManiaModGravity.cs
@@ -7,7 +7,6 @@ using osu.Game.Rulesets.Mania.UI;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Graphics;
 using osu.Game.Rulesets.Mania.Timing;
-using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Timing;
 using osu.Game.Rulesets.Mania.Objects.Drawables;
 
@@ -23,21 +22,21 @@ namespace osu.Game.Rulesets.Mania.Mods
 
         public void ApplyToHitRenderer(ManiaHitRenderer hitRenderer, ref List<SpeedAdjustmentContainer>[] hitObjectTimingChanges, ref List<SpeedAdjustmentContainer> barlineTimingChanges)
         {
-            foreach (HitObject obj in hitRenderer.Objects)
+            // We have to generate one speed adjustment per hit object for gravity
+            foreach (ManiaHitObject obj in hitRenderer.Objects)
             {
-                var maniaObject = obj as ManiaHitObject;
-                if (maniaObject == null)
-                    continue;
-
                 MultiplierControlPoint controlPoint = hitRenderer.CreateControlPointAt(obj.StartTime);
+                // Beat length has too large of an effect for gravity, so we'll force it to a constant value for now
                 controlPoint.TimingPoint.BeatLength = 1000;
 
-                hitObjectTimingChanges[maniaObject.Column].Add(new ManiaSpeedAdjustmentContainer(controlPoint, ScrollingAlgorithm.Gravity));
+                hitObjectTimingChanges[obj.Column].Add(new ManiaSpeedAdjustmentContainer(controlPoint, ScrollingAlgorithm.Gravity));
             }
 
+            // Like with hit objects, we need to generate one speed adjustment per bar line
             foreach (DrawableBarLine barLine in hitRenderer.BarLines)
             {
                 var controlPoint = hitRenderer.CreateControlPointAt(barLine.HitObject.StartTime);
+                // Beat length has too large of an effect for gravity, so we'll force it to a constant value for now
                 controlPoint.TimingPoint.BeatLength = 1000;
 
                 barlineTimingChanges.Add(new ManiaSpeedAdjustmentContainer(controlPoint, ScrollingAlgorithm.Gravity));
diff --git a/osu.Game.Rulesets.Mania/Timing/BasicScrollingDrawableTimingSection.cs b/osu.Game.Rulesets.Mania/Timing/BasicScrollingDrawableTimingSection.cs
index 58f7e522be..f579567a6c 100644
--- a/osu.Game.Rulesets.Mania/Timing/BasicScrollingDrawableTimingSection.cs
+++ b/osu.Game.Rulesets.Mania/Timing/BasicScrollingDrawableTimingSection.cs
@@ -6,21 +6,24 @@ using osu.Game.Rulesets.Timing;
 
 namespace osu.Game.Rulesets.Mania.Timing
 {
+    /// <summary>
+    /// A <see cref="DrawableTimingSection"/> which scrolls relative to the control point start time.
+    /// </summary>
     internal class BasicScrollingDrawableTimingSection : DrawableTimingSection
     {
-        private readonly MultiplierControlPoint timingSection;
+        private readonly MultiplierControlPoint controlPoint;
 
-        public BasicScrollingDrawableTimingSection(MultiplierControlPoint timingSection)
+        public BasicScrollingDrawableTimingSection(MultiplierControlPoint controlPoint)
             : base(Axes.Y)
         {
-            this.timingSection = timingSection;
+            this.controlPoint = controlPoint;
         }
 
         protected override void Update()
         {
             base.Update();
 
-            Y = (float)(timingSection.StartTime - Time.Current);
+            Y = (float)(controlPoint.StartTime - Time.Current);
         }
     }
 }
diff --git a/osu.Game.Rulesets.Mania/Timing/GravityScrollingDrawableTimingSection.cs b/osu.Game.Rulesets.Mania/Timing/GravityScrollingDrawableTimingSection.cs
index b0e41cfbae..df8daa43dd 100644
--- a/osu.Game.Rulesets.Mania/Timing/GravityScrollingDrawableTimingSection.cs
+++ b/osu.Game.Rulesets.Mania/Timing/GravityScrollingDrawableTimingSection.cs
@@ -6,14 +6,17 @@ using osu.Game.Rulesets.Timing;
 
 namespace osu.Game.Rulesets.Mania.Timing
 {
+    /// <summary>
+    /// A <see cref="DrawableTimingSection"/> that emulates a form of gravity where hit objects speed up over time.
+    /// </summary>
     internal class GravityScrollingDrawableTimingSection : DrawableTimingSection
     {
-        private readonly MultiplierControlPoint timingSection;
+        private readonly MultiplierControlPoint controlPoint;
 
-        public GravityScrollingDrawableTimingSection(MultiplierControlPoint timingSection)
+        public GravityScrollingDrawableTimingSection(MultiplierControlPoint controlPoint)
             : base(Axes.Y)
         {
-            this.timingSection = timingSection;
+            this.controlPoint = controlPoint;
         }
 
         protected override void UpdateAfterChildren()
@@ -21,9 +24,9 @@ namespace osu.Game.Rulesets.Mania.Timing
             base.UpdateAfterChildren();
 
             // The gravity-adjusted start position
-            float startPos = (float)computeGravityTime(timingSection.StartTime);
+            float startPos = (float)computeGravityTime(controlPoint.StartTime);
             // The gravity-adjusted end position
-            float endPos = (float)computeGravityTime(timingSection.StartTime + RelativeChildSize.Y);
+            float endPos = (float)computeGravityTime(controlPoint.StartTime + RelativeChildSize.Y);
 
             Y = startPos;
             Height = endPos - startPos;
diff --git a/osu.Game/Rulesets/Timing/DrawableTimingSection.cs b/osu.Game/Rulesets/Timing/DrawableTimingSection.cs
index 131dc1dc0e..846df34e25 100644
--- a/osu.Game/Rulesets/Timing/DrawableTimingSection.cs
+++ b/osu.Game/Rulesets/Timing/DrawableTimingSection.cs
@@ -1,7 +1,6 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
-using System;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Caching;
@@ -24,19 +23,21 @@ namespace osu.Game.Rulesets.Timing
     /// </para>
     ///
     /// <para>
-    /// This container will auto-size to the total size of its children along the desired auto-sizing axes such that the reasulting size
-    /// of this container will also be a time value.
+    /// This container will auto-size to the total duration of the contained hit objects along the desired auto-sizing axes such that the resulting size
+    /// of this container will be a value representing the total duration of all contained hit objects.
     /// </para>
     ///
     /// <para>
-    /// This container is and must always be relatively-sized and positioned to its such that the parent can utilise
-    /// <see cref="Container{T}.RelativeChildSize"/> and <see cref="Container{T}.RelativeChildOffset"/> to apply further time offsets
-    /// to this collection of hit objects.
+    /// This container is and must always be relatively-sized and positioned to its such that the parent can utilise <see cref="Container{T}.RelativeChildSize"/>
+    /// and <see cref="Container{T}.RelativeChildOffset"/> to apply further time offsets to this collection of hit objects.
     /// </para>
     /// </summary>
     public abstract class DrawableTimingSection : Container<DrawableHitObject>
     {
         private readonly BindableDouble visibleTimeRange = new BindableDouble();
+        /// <summary>
+        /// Gets or sets the range of time that is visible by the length of this container.
+        /// </summary>
         public BindableDouble VisibleTimeRange
         {
             get { return visibleTimeRange; }
@@ -57,18 +58,8 @@ namespace osu.Game.Rulesets.Timing
         {
             this.autoSizingAxes = autoSizingAxes;
 
+            RelativeSizeAxes = Axes.Both;
             RelativePositionAxes = Axes.Both;
-
-            // We need a default size since RelativeSizeAxes is overridden
-            Size = Vector2.One;
-        }
-
-        public override Axes AutoSizeAxes { set { throw new InvalidOperationException($"{nameof(DrawableTimingSection)} must always be relatively-sized."); } }
-
-        public override Axes RelativeSizeAxes
-        {
-            get { return Axes.Both; }
-            set { throw new InvalidOperationException($"{nameof(DrawableTimingSection)} must always be relatively-sized."); }
         }
 
         public override void InvalidateFromChild(Invalidation invalidation)
diff --git a/osu.Game/Rulesets/Timing/MultiplierControlPoint.cs b/osu.Game/Rulesets/Timing/MultiplierControlPoint.cs
index 2037174a5c..c6b5fa83e6 100644
--- a/osu.Game/Rulesets/Timing/MultiplierControlPoint.cs
+++ b/osu.Game/Rulesets/Timing/MultiplierControlPoint.cs
@@ -10,27 +10,46 @@ namespace osu.Game.Rulesets.Timing
     public class MultiplierControlPoint : IJsonSerializable, IComparable<MultiplierControlPoint>
     {
         /// <summary>
-        /// The time in milliseconds at which this control point starts.
+        /// The time in milliseconds at which this <see cref="MultiplierControlPoint"/> starts.
         /// </summary>
         public readonly double StartTime;
 
         /// <summary>
-        /// The multiplier which this control point provides.
+        /// The multiplier which this <see cref="MultiplierControlPoint"/> provides.
         /// </summary>
         public double Multiplier => 1000 / TimingPoint.BeatLength / DifficultyPoint.SpeedMultiplier;
 
+        /// <summary>
+        /// The <see cref="TimingControlPoint"/> that provides the timing information for this <see cref="MultiplierControlPoint"/>.
+        /// </summary>
         public TimingControlPoint TimingPoint = new TimingControlPoint();
+
+        /// <summary>
+        /// The <see cref="DifficultyControlPoint"/> that provides additional difficulty information for this <see cref="MultiplierControlPoint"/>.
+        /// </summary>
         public DifficultyControlPoint DifficultyPoint = new DifficultyControlPoint();
 
+        /// <summary>
+        /// Creates a <see cref="MultiplierControlPoint"/>. This is required for JSON serialization
+        /// </summary>
         public MultiplierControlPoint()
         {
         }
 
+        /// <summary>
+        /// Creates a <see cref="MultiplierControlPoint"/>.
+        /// </summary>
+        /// <param name="startTime">The start time of this <see cref="MultiplierControlPoint"/>.</param>
         public MultiplierControlPoint(double startTime)
         {
             StartTime = startTime;
         }
 
+        /// <summary>
+        /// Creates a <see cref="MultiplierControlPoint"/> by copying another <see cref="MultiplierControlPoint"/>.
+        /// </summary>
+        /// <param name="startTime">The start time of this <see cref="MultiplierControlPoint"/>.</param>
+        /// <param name="other">The <see cref="MultiplierControlPoint"/> to copy.</param>
         public MultiplierControlPoint(double startTime, MultiplierControlPoint other)
             : this(startTime)
         {
diff --git a/osu.Game/Rulesets/Timing/SpeedAdjustmentCollection.cs b/osu.Game/Rulesets/Timing/SpeedAdjustmentCollection.cs
index 550f77dab2..03bbe6528d 100644
--- a/osu.Game/Rulesets/Timing/SpeedAdjustmentCollection.cs
+++ b/osu.Game/Rulesets/Timing/SpeedAdjustmentCollection.cs
@@ -15,14 +15,16 @@ namespace osu.Game.Rulesets.Timing
     /// A collection of <see cref="SpeedAdjustmentContainer"/>s.
     ///
     /// <para>
-    /// This container provides <see cref="VisibleTimeRange"/> for the <see cref="SpeedAdjustmentContainer"/>s.
+    /// This container redirects any <see cref="DrawableHitObject"/>'s added to it to the <see cref="SpeedAdjustmentContainer"/>
+    /// which provides the speed adjustment active at the start time of the hit object. Furthermore, this container provides the
+    /// necessary <see cref="VisibleTimeRange"/> for the contained <see cref="SpeedAdjustmentContainer"/>s.
     /// </para>
     /// </summary>
     public class SpeedAdjustmentCollection : Container<SpeedAdjustmentContainer>
     {
         private readonly BindableDouble visibleTimeRange = new BindableDouble();
         /// <summary>
-        /// The amount of time visible by span of this container.
+        /// Gets or sets the range of time that is visible by the length of this container.
         /// For example, only hit objects with start time less than or equal to 1000 will be visible with <see cref="VisibleTimeRange"/> = 1000.
         /// </summary>
         public Bindable<double> VisibleTimeRange
@@ -32,15 +34,16 @@ namespace osu.Game.Rulesets.Timing
         }
 
         /// <summary>
-        /// Adds a hit object to the most applicable timing section in this container.
+        /// Adds a hit object to the <see cref="SpeedAdjustmentContainer"/> which provides the speed adjustment
+        /// active at the start time of the hit object.
         /// </summary>
         /// <param name="hitObject">The hit object to add.</param>
         public void Add(DrawableHitObject hitObject)
         {
-            var target = timingSectionFor(hitObject);
+            var target = adjustmentContainerFor(hitObject);
 
             if (target == null)
-                throw new ArgumentException("No timing section could be found that can contain the hit object.", nameof(hitObject));
+                throw new ArgumentException("No speed adjustment could be found that can contain the hit object.", nameof(hitObject));
 
             target.Add(hitObject);
         }
@@ -51,33 +54,34 @@ namespace osu.Game.Rulesets.Timing
             base.Add(speedAdjustment);
         }
 
-        protected override IComparer<Drawable> DepthComparer => new TimingSectionReverseStartTimeComparer();
+        protected override IComparer<Drawable> DepthComparer => new SpeedAdjustmentContainerReverseStartTimeComparer();
 
         /// <summary>
-        /// Finds the most applicable timing section that can contain a hit object. If the hit object occurs before the first (time-wise)
-        /// timing section, then the timing section returned is the first (time-wise) timing section.
+        /// Finds the <see cref="SpeedAdjustmentContainer"/> which provides the speed adjustment active at the start time
+        /// of a hit object. If there is no <see cref="SpeedAdjustmentContainer"/> active at the start time of the hit object,
+        /// then the first (time-wise) speed adjustment is returned.
         /// </summary>
-        /// <param name="hitObject">The hit object to contain.</param>
-        /// <returns>The last (time-wise) timing section which can contain <paramref name="hitObject"/>. Null if no timing section exists.</returns>
-        private SpeedAdjustmentContainer timingSectionFor(DrawableHitObject hitObject) => Children.FirstOrDefault(c => c.CanContain(hitObject)) ?? Children.LastOrDefault();
+        /// <param name="hitObject">The hit object to find the active <see cref="SpeedAdjustmentContainer"/> for.</param>
+        /// <returns>The <see cref="SpeedAdjustmentContainer"/> active at <paramref name="hitObject"/>'s start time. Null if there are no speed adjustments.</returns>
+        private SpeedAdjustmentContainer adjustmentContainerFor(DrawableHitObject hitObject) => Children.FirstOrDefault(c => c.CanContain(hitObject)) ?? Children.LastOrDefault();
 
         /// <summary>
-        /// Compares two timing sections by their start time, falling back to creation order if their start time is equal.
-        /// This will compare the two timing sections in reverse order.
+        /// Compares two speed adjustment containers by their control point start time, falling back to creation order
+        // if their control point start time is equal. This will compare the two speed adjustment containers in reverse order.
         /// </summary>
-        private class TimingSectionReverseStartTimeComparer : ReverseCreationOrderDepthComparer
+        private class SpeedAdjustmentContainerReverseStartTimeComparer : ReverseCreationOrderDepthComparer
         {
             public override int Compare(Drawable x, Drawable y)
             {
-                var timingChangeX = x as SpeedAdjustmentContainer;
-                var timingChangeY = y as SpeedAdjustmentContainer;
+                var speedAdjustmentX = x as SpeedAdjustmentContainer;
+                var speedAdjustmentY = y as SpeedAdjustmentContainer;
 
                 // If either of the two drawables are not hit objects, fall back to the base comparer
-                if (timingChangeX?.MultiplierControlPoint == null || timingChangeY?.MultiplierControlPoint == null)
+                if (speedAdjustmentX?.MultiplierControlPoint == null || speedAdjustmentY?.MultiplierControlPoint == null)
                     return base.Compare(x, y);
 
                 // Compare by start time
-                int i = timingChangeY.MultiplierControlPoint.StartTime.CompareTo(timingChangeX.MultiplierControlPoint.StartTime);
+                int i = speedAdjustmentY.MultiplierControlPoint.StartTime.CompareTo(speedAdjustmentX.MultiplierControlPoint.StartTime);
 
                 return i != 0 ? i : base.Compare(x, y);
             }
diff --git a/osu.Game/Rulesets/Timing/SpeedAdjustmentContainer.cs b/osu.Game/Rulesets/Timing/SpeedAdjustmentContainer.cs
index a6f94ccf6c..7021c1435b 100644
--- a/osu.Game/Rulesets/Timing/SpeedAdjustmentContainer.cs
+++ b/osu.Game/Rulesets/Timing/SpeedAdjustmentContainer.cs
@@ -1,7 +1,6 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
-using System;
 using osu.Framework.Allocation;
 using osu.Framework.Configuration;
 using osu.Framework.Graphics;
@@ -12,18 +11,29 @@ using OpenTK;
 namespace osu.Game.Rulesets.Timing
 {
     /// <summary>
-    /// A container for hit objects which applies applies the speed adjustments defined by the <see cref="Timing.MultiplierControlPoint"/> properties
-    /// to its <see cref="Container{T}.Content"/> to affect the <see cref="DrawableTimingSection"/> scroll speed.
+    /// A container for hit objects which applies applies the speed adjustments defined by the properties of a <see cref="Timing.MultiplierControlPoint"/>
+    /// to affect the scroll speed of the contained <see cref="DrawableTimingSection"/>.
+    ///
+    /// <para>
+    /// This container must always be relatively-sized to its parent to provide the speed adjustments. This container will provide the speed adjustments
+    /// by modifying its size while maintaining a constant <see cref="Container{T}.RelativeChildSize"/> for its children
+    /// </para>
     /// </summary>
     public abstract class SpeedAdjustmentContainer : Container<DrawableHitObject>
     {
         private readonly Bindable<double> visibleTimeRange = new Bindable<double>();
+        /// <summary>
+        /// Gets or sets the range of time that is visible by the length of this container.
+        /// </summary>
         public Bindable<double> VisibleTimeRange
         {
             get { return visibleTimeRange; }
             set { visibleTimeRange.BindTo(value); }
         }
 
+        /// <summary>
+        /// The <see cref="MultiplierControlPoint"/> which provides the speed adjustments for this container.
+        /// </summary>
         public readonly MultiplierControlPoint MultiplierControlPoint;
 
         protected override Container<DrawableHitObject> Content => content;
@@ -34,12 +44,14 @@ namespace osu.Game.Rulesets.Timing
         /// <summary>
         /// Creates a new <see cref="SpeedAdjustmentContainer"/>.
         /// </summary>
-        /// <param name="multiplierControlPoint">The multiplier control point that provides the speed adjustments for this container.</param>
-        /// <param name="scrollingAxes">The axes through which this drawable timing section scrolls through.</param>
+        /// <param name="multiplierControlPoint">The <see cref="MultiplierControlPoint"/> which provides the speed adjustments for this container.</param>
+        /// <param name="scrollingAxes">The axes through which the content of this container should scroll through.</param>
         protected SpeedAdjustmentContainer(MultiplierControlPoint multiplierControlPoint, Axes scrollingAxes)
         {
             this.scrollingAxes = scrollingAxes;
 
+            RelativeSizeAxes = Axes.Both;
+
             MultiplierControlPoint = multiplierControlPoint;
         }
 
@@ -54,12 +66,6 @@ namespace osu.Game.Rulesets.Timing
             AddInternal(content = timingSection);
         }
 
-        public override Axes RelativeSizeAxes
-        {
-            get { return Axes.Both; }
-            set { throw new InvalidOperationException($"{nameof(SpeedAdjustmentContainer)} must always be relatively-sized."); }
-        }
-
         protected override void Update()
         {
             float multiplier = (float)MultiplierControlPoint.Multiplier;
@@ -77,7 +83,7 @@ namespace osu.Game.Rulesets.Timing
         /// <summary>
         /// Creates the container which handles the movement of a collection of hit objects.
         /// </summary>
-        /// <returns>The drawable timing section.</returns>
+        /// <returns>The <see cref="DrawableTimingSection"/>.</returns>
         protected abstract DrawableTimingSection CreateTimingSection();
     }
 }
\ No newline at end of file
diff --git a/osu.Game/Rulesets/UI/HitRenderer.cs b/osu.Game/Rulesets/UI/HitRenderer.cs
index 43c350184e..056ee2044f 100644
--- a/osu.Game/Rulesets/UI/HitRenderer.cs
+++ b/osu.Game/Rulesets/UI/HitRenderer.cs
@@ -120,6 +120,11 @@ namespace osu.Game.Rulesets.UI
         /// </summary>
         public Beatmap<TObject> Beatmap;
 
+        /// <summary>
+        /// All the converted hit objects contained by this hit renderer.
+        /// </summary>
+        public override IEnumerable<HitObject> Objects => Beatmap.HitObjects;
+
         /// <summary>
         /// The mods which are to be applied.
         /// </summary>
@@ -206,7 +211,10 @@ namespace osu.Game.Rulesets.UI
 
         public sealed override bool ProvidingUserCursor => !HasReplayLoaded && Playfield.ProvidingUserCursor;
 
-        public override IEnumerable<HitObject> Objects => Beatmap.HitObjects;
+        /// <summary>
+        /// All the converted hit objects contained by this hit renderer.
+        /// </summary>
+        public new IEnumerable<TObject> Objects => Beatmap.HitObjects;
 
         protected override bool AllObjectsJudged => drawableObjects.All(h => h.Judged);